How 'bout a breezer? You might be able to get one used for that price range (I think otherwise, they're 6-800). They're super upright - particularly in the U Frame, and come with commuting goodies (fenders, rack, etc). I'm looking at one for short errands - I rode one and was *completely* upright - very little if any weight on the arms. Just steering.

Glad to hear you're getting back out there - be gentle with yourself - you've been through a lot.

CA