It'll be a real stretch coming from a T-2 and having worked for a small firm the previous summer. But it is possible. the best thing to do would be to target every single firm that comes to your school for OCI, and those who don't, by mail or by OCI application if applicable.
Stress your grades and class rank within the first couple sentences of your cover letter. You're obviously qualified, it's just a matter of getting them to notice.
Then state precisely why you are interested in their firm (tailoring a sentence or two for each application).
If you're in the Bay Area for example, I would send letters to each of the 50 or so possibilities. To give you perspective, I was top 5% from a T-1 last Fall, having worked at a large law firm the previous summer (bottom half of the Vault 100). I applied through OCI and got almost every interview for those firms interviewing 3L's I applied for. You'll likely be in a similar boat. As for letters, I mailed out about 20 and got two call-backs from those. OCI's the best bet but letter-writing, stressing your rank, is important as well.