A question about W-4 tax things?

I currently would make a projected $27,420.00 ($2108.00ish per month) in 2011 this usually equates to about 869.00 per pay period (bi-weekly) if I worked at 40 hours 52 weeks per year. This does not include what 1/4 incentives I MAY earn, holiday pay or overtime (not usually). I have no children, no spouse or live in partner. I currently claim 2. 1 for myself and 1 for being single with one job. As it stands right now month to month I pay 675 for rent, 464.12 for car and insurance, 300 in student loans and an astronomical amount for gas. MY QUESTION is can I claim exempt for just one or two months this year (2011) to catch up and then put it back at 2. I don't care if I have to balance it out in exemptions in tax season I just had to buy this new to me/used vehicle (not a hybrid) with a deferred down payment and after doing my budget I simply just don't have a single penny to spend on food or for a security in case gas runs low. LET ME POINT OUT THIS: I DO NOT EAT OUT, I DO NOT GO OUT, I do not smoke, drink or pay any monthly dues to convenience/leisure services nor do I have any credit card debt. I am staying home except to drive to work and back. I just need some more sustenance than ramen (once per day). IF everything was due on the 1st and I got all $1700ish at once I would be fine. But I find my self putting off this payment and that payment and its just a vicious cycle. I have done the math and found that if I claimed exempt for 2 months (Feb and March) I would be just fine and things would go as smooth as they were before 2 weeks ago. IS IT ILLEGAL (not just immoral) to claim federal tax liability exempt for just those two months. Last thing I have to say is I could care less about a big refund because I don't account for it. I just need to eat. Can someone give me some advice or direct me to some free source for help. If it helps to know I always donate 2% of each check to United Way so I don't feel right with going to local food banks.