Looking to find sublettor

[spkrause]

Hello, I just moved in to an apartment with my girlfriend, and we both would like to leave since it's too small for the both of us (I saw the place before moving in, she did not).

I signed the lease, she did not do so yet. I also paid one month's rent plus one month's security.

Question, if we find someone to take over the lease, will the LL be legally obligated to give us the security deposit back? Or better yet, can we legally find a sublettor to pay us said deposit?