Subletting violation-without landlord's permission

Hello,

I rent a 2 bed room apartment, and my roommate live in the smaller room in my apartment. I made a co-tenant agreement with a roommate from 6/1/08 to 7/31/09 without the landload's written consent. Each of us contributes the half of the security deposit. The original contract expires in 7/31/09, so I already sent a written notice to landload that I will move out in 7/31.  My landload sent me a letter that says it is breach of NJ original lease.

Since co-tenant agreement that I and my roommate made made is until 7/31/09, I want my roommate to pay for the full amount of July rent fee, and I will give back the half of the security deposit to my roommate within 30 days when we leave.

My roommate is arguing me that I should give the half of the security deposit immediately, and she doesnt want to pay for July rent. What should I do?   &...

1. How should I handle for July rent fee? My roommate is responsible for July rent? 

2. Should I give the half of the deposit back to my roommate? When?

3. I and my roommate still have right to stay in the aparment for 30 days?

4. I know I breach the original lease agreement, then..Co-tenant agreement still has legal power?

Thank you for reading this. I appreciate your time. If you relpy me, it would me very helpful

It reads to me as if the roommate is actually your subtenant.

If she owes you July rent then you need to press for same.

Whe she moves at proper end of lease you pay her back the security-less any of her damages etc  even if your LL has yet to pay you