Here’s my translation

Alan

Og er þeir flugu upp yfir bergsnösina hljóp hann Björn þá upp á bergið og lagði málaspjóti á drekanum. 
And when they flew up over the-rocky-projection he Björn leapt then up onto the-rock and thrust an inlaid-spear at the-dragon.

En er hann hreppti áverkann þá hljóp úr sárinu mikið blóð í andlit honum og fékk hann af því skjótan bana en blóðið og eitrið kom á fót Hyrningi og sló þar í æðiverk svo að hann mátti trautt standast.
But (and) when he (the dragon) received the-wound then much blood ran out-of the-wound in his face and he got from that a swift (adj) death but the-blood and the-poison (eitr + art) came on (the) foot of Hyrningr and an excruciating-pain struck there-in so that could scarcely (trauðr) stand (keep his feet).

Nú er að segja frá Þóri og hans félögum að þeir afla sér mikils fjár í hellinum svo að það var margra manna fullfengi í gulli og mörgum dýrgripum. 
Now (one) is to say about Þórir and his comrades that they earnt for themselves much wealth in the-cave so that that was (the) ample-booty of many persons (men) in gold and many valuable-treasures (ie there was treasure enough for many men).

Er svo sagt að þeir hafi á þriðja degi verið í Valshelli. 
(It) is thus said that they had on a third day (ie for three days?) been in Valshelli (Valr’s-Cave)

Síðan las Þórir sig fyrstur upp og dró upp fé og þá félaga sína. 
After-that Þórir first hauled himself up and drew up (the) wealth and then his comrades.

Tók hann þá fót Hyrnings og strauk með glófunum og tók þegar úr allan verkinn. 
He then took Hyrningr’s foot and stroked (it) with the-gloves (plural) and took immediately all the-pain out-of (it)

Nú skyldi Þórir skipta fénu og varð einn hluturinn ávallt mestur og fór svo nokkurum sinnum.
Noe Þórir should divide the-wealth and the one share became (ie was) always greatest and (it) went thus for some time (does this mean that however he tried to divide it up equally one man’s share always seemed to be greater than the others?)

Þá mælti Ketilbjörn: "Fóstbróðir," sagði hann, "þú hefir mest unnið til fjár þessa. 
Then Ketilbjörn spoke: “Foster-brother,” said he, “you have done (the) most so as to earn this wealth (see vinna til fjár, under vinna, Z12).

Nú vil eg gefa þér minn hlut."
I want to now give you my share.”

Þá mælti Þórhallur þvílíkum orðum. 
Then Þórhallr spoke with such-like (ie similar) words

Þórir varð allléttbrúnn við þetta og varðveitir nú féið. 
Þórir became (ie was) of-very-cheerful-countenance (grinning like a Cheshire cat) with this and kept the-wealth.

En skipt var gullinu Agnarsnaut með félögum Þóris og hefir hver þeirra mörk gulls. 
But (and) (using?) Agnarr’s-Gift (I’m wondering how the accusative works here in a passive expression?) (it) was divided in the-gold (ie the gold was divided using Agnarr’s gift) among (the) comrades of Þórir and each of them has (takes, gets) a mark of gold

Hann gaf og sinn grip hverjum þeirra. 
He gave also his valuable-treasure to each of them

Hyrningi gaf hann sverðið Agnarsnaut. 
To Hyrningr he gave the-sword Agnarr’s-Gift.

Eftir það fóru þeir aftur til Úlfs og vildi Þórir segja frá tíðindum. 
After that they journeyed back to Úlfr and Þórir wanted to say (to him) about tidings.

Þeir dvöldust um hríð með Úlfi og gerði Þórir þá járnviðjar um kistur sínar og læsti vandlega Valshellisgull og lét alla sína félaga á sinn kost þann vetur.
The stayed for a while with Úlfr and Þórir made then iron-wires about his chests and carefully locked-up (the) Valr’s-Cave-Gold and placed all his companion at his cost (expense) that winter

5. kafli
Chapter 5

Eftir það fóru þeir suður til Þrándheims og fundu þar Sigmund. 
After that they journeyed south to Trondheim and found (met) Sigmundr there.

Var það við jól. 
That was at (or towards) Yule.

Þórir sagði Sigmundi frá ferðum þeirra. 
Þórir said to Sigmundr about their travels.

En Sigmundur bað þá þegar eftir jólin fara úr ríki Noregskonungs. 
But (and) Sigmundr bade them immediately after Yule to go out-of (the) kingdom (ríki, Z3)of Norway’s-king.

Hann sendi þá inn í Þrándheim og fékk þeim eyki austur um Kjöl til Jamtalands og svo til Gestrekalands. 
He sent them inwards to Trondheim and got them a cart east by Kjöll to Jamtaland (Jämtland, Central Sweden) and so to Gestrekaland (Gästrikland, Eastern Sweden)

Þaðan fóru þeir á Elfarskóg og ætla til Svíþjóðar, sá skógur er fjögurra rasta og tuttugu breiður, og vissu eigi hvar þeir fóru.
From-there they journeyed to Elfarskógr ((Gotha-) River-Forest) and intended (to go) to Sweden, that forest is of four and twenty rösts) wide (1 röst = 4-5 miles), and (they) knew not where they were-going.