I did this myself in both my front and back yards, on approx 1/4th acre. I don't know how handy you are, but this is really an easy job, especially if you're looking to have the whole thing sodded. Probably the most difficult job, is digging the trenches and covering it all back up. Even if you're not handy, you can do the grunt-work and lay-out all the lines, then have a plumber come-by to hook up the final stuff. If you're going to have sod laid, you can 'go wild' with your trenches, not worry about patching the lawn, and have the crew doing the sod-work finish the final grade.
A buddy and I did the entire job, including touch-up work on the lawn, in a short weekend (work a little, break a little, etc...). Since you don't have the $$ to have both jobs done, do the sprinkler yourself and have a crew do the sod. You can find all you need in your home improvement store (Lowes, Home Depot, Menards, etc), along with some helpful stuff for the do-it-yourselfer. Also, I remember Rainbird had a good site on line for laying-out the lines, estimating what you'll need, etc. Even if you hire it done, I'd check these resources to give yourself an idea of what will be needed, and the cost involved. Also, depending on your location, you may have to contend with frost, so knowing in advance what will be required, helps prevent problems in the future. Finally, even though it's "automatic", it still requires maintenance, and even if you have it installed, knowing this system will help you do your own repairs in the future (instead of calling out a repair guy at the beginning and end of every season).