I got a new job last year much closer to my house so I started biking to work. Used my dad's old Huffy all last year and now it's on a last dying breath. I went to the two main bike shops around looking for a road bike in the $300 range and all of them were clean out of anything in my size. The Huffy fits me pretty good, I haven't measured it but I get about 1" of standing clearance from the top tube and my knees or back have never complained. Do you think it would be wise to overhaul this frame and make it fixed gear in the process or should I try to find another used bike? I can't afford anything new right now (broke college student).

I'd like to put some money into this as its really my only option locally right now. Could any give me a quick run down of what I would need to buy (mostly price-friendly, cheap parts)??? I can live with the bars and seat for now. Thanks.

Here are some pictures: