The computer is located on the right hand side of the engine compartment in front of the right hand wheel. Here is an illustration.
Before you jump to any conclusions though I would recommend having this vehicle scanned for trouble codes. This will require a scan tool. If you do not have one of these available to you, you may want to check with you local auto part store to see if they do free engine diagnostic scans. This would give you a trouble code regarding your exact failure. If you can do this and post the code, I can further assist you. Good luck!
The module itself costs $512.62 from the dealer. This would be pt#16228016. I would check with your dealer to verify this is the correct unit for your car though. You may also save a few bucks buying an aftermarket remanufactured unit from autozone or a parts place like that. I would also like to tell you that there hase been a large amount of these that have actually suffered from moisture intrusion do to the placement of this module.