yes, you can stay for 60 days grace period after your OPT expires. As in my case, my OPT started a month later and i was given 60 days grace period. During this grace period, i applied for Masters, and i received a new I-20 within this grace period. You need to apply for college asap, and get an I-20 before the 60 days grace period is over. You can apply for Kaplan for the time being. They issue I=20 for few programs like iGRE, iGMAT, TOEFL or USMLE programs. I did iGRE with them for 3 months to maintain F1 status. Since your OPT expires in october, your grace period is until december. So you need to apply for a college and get an I-20 before december.