Smoblikat: HIGHLY unlikely you'll see a Piledriver till the end of the year. From what we know, it won't go into production until late Q3 so end of the year is the earliest. Second, it will be faster than Bulldozer but at best as fast as a 2600k and perhaps a little slower. This is my hunch from what I've read. Next the high end Piledriver, tentatively listed as a 8350 will mostlikely be clock at 4 Ghz and Turbo at 4.2 or at most 4.4 Ghz. A little research shows that at best this will match a 2600k and the Ivy Bridge 3770k will be faster. Next the price will most likely be @$300-320 so do you wait for this? Not me. You already have a chip (2500k) that is faster than a Bulldozer ( see this link
http://www.anandtech.com/bench/Product/434?vs=288)
Now how about a Bulldozer vs a 3770k?
http://www.anandtech.com/bench/Product/434?vs=551
I don't see a PileDriver making up the difference.
First I would overclock your 2500k to at least 4.Ghz with the stock cooler or 4.4Ghz with a good aftermarket cooler and see if that meets your needs. I would not wait for a Piledriver.