The good news is that if you need help with closing costs, there are ways to minimize these fees. Typically you can ask the seller to contribute to your closing costs and depending on your loan program may even be able to get them all paid by the seller or even through a first time home buyer bond money program (again, that infomation is available through your local lenders). Bear in mind when asking a seller to contribute to your closing costs that their concern will be net dollars, so if you make a reduced offer AND want them to contribute to your closing costs, you are even further reducing the amount of money they will net on the sale and your offer won't appear that desirable to them.
The best way to find out what your actual closing costs would be is to contact a Realtor and a lender. Get an idea of the general price of homes that meet the criteria you are looking for and then get prequalified with a lender and have them put together a "Good Faith Estimate" for you based on the sales price you would expect to pay for a home that you would be interested in paying. A Realtor can also put together an "Estimated Cost to Buyer" sheet so that you would have a much better idea what expenses you would actually incur at closing. Additionally, they will calculate your monthly payment for you at that time as well.
Good luck and happy home hunting! :)