> þar...er Hallgerður er

Yes, literally "there where H. is" (that's where we're to take up the
story now).

> og fóru í liðsbón

MM & HP "and went out to ask others for their support"

I think I covered the other bits you've underlined in my comments for
Patricia, but let me know if there's anything I missed, or made a mess
of explaining!

On a side note, after typing that long message just now and clicking
SEND, Yahoo took me to the sign-in password screen instead of the
"your message has been sent" screen. Luckily, or rather thanks to
bitter experience, I'd taken the precaution of using the "select all"
keys (in Windows, control + a) then copying the text (control + c)
before I tried to send. So I was able to start a new massage and just
paste the text into it (control + v), instead of tearing out my hair.
Phew! A useful habit to get into...