I went through this when trying to put my 1 din display into my car with a 1.5 din radio. I wanst removing the 1.5 din, but the problem is the same.
Lemme guess, you look up your car on the install kit page and it only lists 1.5 din kits right ? :-)
Bottom line is, just disassemble the dash so you can see whats back there.
I was sweating over this and an installer saw me going over all the kits and offered to take a look at the car for me. Long story short, he had a single din adapter we made fit.
But what I learned was that its no big deal. Just take it apart and look at the space you want to mount the single din in. You can almost certainly use any generic single din faceplace and if you cant find brackets to fit exactly, you can often just make some out of light guage metal. They are just angle brackets, the bezel (the radio surround already in you car) is gonna cover most if not all of it up anyway.
Or, alternately, you can just bring the single din piece of equipment with you to any installer (even like Best Buy) and ask them to just mount the unit. If you are doing the rest, just mounting it may cost like $20 - $30.
PDP1170/TRS80/Atari800XL/Amiga500/286/486/P2/P4/C2D/i7 still a newb (but an old newb, been doing this a while) working my way up to "Complete Newb"
Your local electronics store more than likely has a kit for your car. They are usually in the $20-$30 range like Jistari said. They are usually made by Metra or some other companies. Check BestBuy, Circuit City, etc. If it's a GM car then there's a kit for it.
Nick - 08 GG Element Custom 3D-CAD Design, Reverse Engineering and Fabrication