I think you should target programs beginning Mar - Apr 2012.
Here is what I would recommend:
1. Dont quit your job to prepare for the GMAT. You can do that alongside your job. See this link:
https://www.gyanone.com/blog/ (the article on preparing for the GMAT with a full time job)
2. Aim to get the GMAT done by about Jun-Jul 2012 (outer limit). Make sure you give adequate time to get the desired score.
3. Apply in programs starting Jul or Aug 2012 (all programs you are targeting will be open then, most in R1). It is critical that you also give enough time to your applications - not doing this might end up wasting the entire effort.
4. Hopefully get through and join your target school in Mar - Apr 2012.