If these are big firms you're looking at, you're already way behind on the 1L hiring timeline. They started accepting 1L resumes on Dec. 1, and have been setting up interviews for during the winter break.
You need to contact the hiring partner/recruiting coordinator asap (as in, do it yesterday) with your resume. And it's an *excellent* idea to say you'll be in town on certain dates, and would love an opportunity to interview.
And you definitely should get the Guerilla Tactics book to read over break. It seems like you don't know much about the 1L hiring process (waiting for grades is a big no-no, at least if you're trying for big firms). Some schools don't do a great job with info dissemination. This book has great tips for everything from networking to interviewing and everything in between.