Okay, I'll help you with this:
1. if you're adding a discrete chip do not bother upgrading to the 7850 or 6800k, Get an athlon 750/760K they will fit your current motherboards(the 750k is essentially a 6800k without a graphics unit but doesn't matter if you've got a discrete card
2. Your system will probably not need more than 8GB so I wouldn't splash out on 16GB
3. What is your case size as you'll need a bigger PSU for a discrete gpu