Best thing I could tell you to do is 1 of two things:
The first (and probably best) would be to contact a professional photographer in your area. You can ask them what it costs for a sitting (x number of shots, x number of poses, x amount of time, and so forth). Each package offered is going to differ in price. Call around. Don't pick the first one unless you're absolutely sure they're the ones you want to go with.
The 2nd option is to find a local college or university with some type of photography classes. Talk to some of the students, and see if they'll do it for additional experience, or a project. Give them a few bucks for it.
There is a 3rd option. You could always use a digital camera and photo editing software. You'd need at least a 4 megapixel camera, high quality photo paper, and a good, high DPI printer. Then you could print your own. The problem with this is it could run you as much or more than the 1st two options.