How much does it cost for this package
That's a question best answered by simply looking at all the different CS 5.5 packages there are. We don't know what you need.
As for a machine able to run CS 5.5, you'll find System Requirements when you look at the various packages. For a PC, you'll need Win 7 fast processors and a boatload of memory. Personally, I wouldn't run AE 10.5 with anything less than 8 gigs of memory. More is better.
Mac? Windows? Shouldn't make any big difference. Think about what else you'd be doing with your machine before you go opening the wallet to get hardware.