a ATI 3200 HD plays similarish to intels HD 3000, regardless at this price range, getting one 2nd hand like vishalaestro mentions will be best for your budget. good sub 50$ gpus dont appear on the market much(e.g HD 6770 was sold on blackfriday for sub 50$, nothing else) upgrading a gpu from where you are to a gt 610 is not very efficient price to performance gain at all.
off ebay, I would think you can find offhand GTS 450's, HD 4850's, 4870's and possibly 6750's(which perform around the 80ish$ mark gpu tier wise, the 450 or 6750 recommended for DX11 support)