Ooh, ooh--I'm just seeing this thread now, but if you haven't gotten your bike yet, Nancy, check out this one on eBay:
Terry Classic
This is a good-quality bike for a rockin' price.

BTW, I'm no lightweight myself. I have no useful advice to add, since everyone else has already offered plenty, but I do want to add my words of support. And keep this in mind: spandex is slimming!