I linked Freddieâ€™s budget form below, work backwards, start at the end with savings then adjust everything else.
One third is the recommended amount for a mortgage payment, but there are other issues involved as well. My recommendation is that you work with a reputable loan officer to discuss your fiances before moving forward.
There are some new programs for first time homebuyers that you should ask your Realtor and your mortgage bank about that provide up to $7500 tax credit for you if you buy by this summer -- July 1st if I remember correctly. Maybe that will be extended.
If you just cannot afford to purchase right now, perhaps you could find a rent to buy situation where part of your rent would be applied to the purchase price of the home. Just be sure that you are not overpaying for the house to get this situation. We recommend working with a good Buyer's Agent to assist you -- won't cost you anything usually unless you sign an agreement that obligates you to pay. Shop around to find an ABR and/or CRS agent who will work with you by collecting commission from the seller only. Check either of these designations online at REBAC.com and/or CRS.com. Good luck to you!
Years later, on another home, my payments were half my salary. And that was a real struggle. It gave rise to being "house rich but cash poor."
So you should determine what your lifestyle would be if half your salary goes towards a house (factoring in your tax deductions). What can you give up, what can you live with? Look at what your monthly payments would be --- is it do-able? Will you still be able to build up a savings as a reserve account for emergencies, including repairs to the house?