Buying a frame can be a worthwhile investment if you have the tools and knowledge to do this. You will want as many as the old parts to fit on the new frame as possible to keep the costs downs so be aware of seat post sizing, size of headset and bars, bottom bracket threading, OLD of rear wheel. If these components are not compatible, then as the poster says above, it might be more cost effective to just buy new an sell what you have.

I like the Nashbar idea if it fits. You could also post a photo and description of the frame you currently own and maybe someone in this community will have a donor frame or something inexpensive that might work and have it shipped to you. Good luck with your endeavor.