if you want to update to 7.8 use the navfirm method worked for me and my 610 like yourself i got mine dirt cheap from car phone warehouse
since updating my 610 it seems faster and i've had no problems with it
YES it available using nokia care suite, very painless and easy to do, works a dream been using 7.8 on my 610 for nearly a week now and no problems etc.
i am in the UK