you can get one for about $300 here...
http://www.importfan.com/subcatmfgprod.asp?0=360&1=371&2=1173but since is CabonFiber, you might wana think twice about molding it.
they prolly have a contact phone number and you can call them to see if they have a fiberglass version to sell for about $150... then you can mold that for under $100 at a great bodyshop
now, to make it fonctional... you are looking at another $600+ for someone to cut a hole in your roop and fabricate that sucker!
A tip for looking for a good bodyshop... bring your car, and several photos of what you would like to have them do... then drive around to ATLEAST 4 different shops and get prices - tell the guy that you would like to have this done to your car within the month, but also have several more projects planned for your car and so you are looking for a good shop to come back and have it all done at... this way they SHOULD give you a good price and/or recommend a place that can get the job done better (or whatever)
Good luck while looking!
-isaac