Trying to break in from Major O&G company

Title is says it all.

Graduated in Dec of 2010 from a non target in Texas. Got a job at a major (exxon, conocophillips, chevron, etc.) oil company. I've completed my first year here working in Risk/Credit. I've learned a great deal but I've got an itch to move into IB now.

I've been trying for IB since June of last year, even got a second interview at a firm in Dallas in August. Didn't get the job.

I've been able to network some but haven't been dedicated to it the same way a junior in college would be. I sat for the CFA level 1 this past December so I've been busy with that. Now since that hellish experience is over, I have time.

I'm looking to kick start this networking shit again pretty much. I like the job security and nice salary I get here but I'm ready to move into IB.

I had a phone interview with a boutique firm in Houston last friday, I'm hoping I get called for a second interview this week.

My question is this: With my background (non-target) and experience (major oil company) should I be aiming for MM firms or small niche boutiques?

I am tyring to understand my chances of actually being able to break into a firm that I actually like. I want to do my MBA a few years down the line so I don't want to screw up my chances at a good MBA program!

Thanks