What motherboard are you running?
You could always try to find a used 6-core processor for your current computer, of the I7 970 975x 980 980x or 990x variety.
However for the price of a Haswell I7 you can get into an entry level I7 3820 system. Keep in mind that the 2011 socket should be getting a refresh soon so there will probably be a replacement in the +/- $350 range. And no the old CPU's won't drop in price, except for maybe an individual retailer clearing out.
From my understand Nvidia GPU's are the way to go for Adobe. Something like the 660 or 650ti boost would be around your price range. Please stick with something 2gb of vram or higher.
Here's link to a list of recommended power supplies.
. It was updated a couple of months ago. Something in the 600-700 range is more than enough.
For storage I suggest getting a 250gb SSD as you can easily find them in the sub $200 range. Paying more than that you don't get a huge performance increase. Then get a standard 1tb 7200rpm drive for storage, If necessary. I would use your old one for storage at first and see how it goes for you. You could make a 20gb (or so) partition on your ssd to cache it, using "Intel Rapid Storage Technology". Thus using the ssd as a bigger faster buffer for the mechanical drive.
I am assuming that you'r not using this for professional video editing but rather school or your own fancy, so I suggest this sequence of upgrades;
PSU - no point in blowing up new components
SSD - Will seriously make ANY computer feel 10x faster
GPU - now you can start really getting into the Adobe madness. And maybe paying some A+ game titles..?
CPU Cooler- even something like the coolermaster hyper 212 will let you get a nice cool overclock
If you can find a cheap set of triple channel or even 2 channel memory (2x4) @ 1600mhz + it would be a good investment
Now when your finally sitting there going ugh my processor is too slow. upgrade your cpu and board.