Do a search on the board for tips on starting an egnine that's sat for awhile. You'll find lots of posts with very good suggestions.
A couple of "must-dos" are to change the fuel and fuel filter, and change the oil. Some people recommend pre-oiling the cylinders with Marvel Mystery Oil before you try to turn it over. The suggestion that you turn it over by hand is a good one.
As to buying parts...why, buy them at Pelican Parts, of course. Carpet and seat covers can be obtained at
www.worlduph.com,
www.autobahninteriors.com, and
www.autosintl.com.
Also, get yourself copies of "101 Projects for Your Porsche" and the Bentley service manual.
Have fun. Good luck.