When is the deadline for when a Marine Poolee can p the IST?

I'm a reservist and I have been in the DEP since March 1, 2011. I've been to three Poolee Functions and I've only been able to p the crunches test. I'm set to ship July 18, 2011. I would also like some tips in getting in better shape. I DO NOT want to fail, looking for all help I can get. Thanks you much!