Dude no. I highly doubt that system will be a good upgrade to you.
In fact I think it would be a step down for you.
In turms of graphics, yours out powers that system on Ebay by so much its not even funny.
For CPU performance, it says it has two of those Xeon CPU's with 6 cores and 12 threads each. That is a huge amount of threads but its older architecture.http://www.cpu-world.com/sspec/SL/SLBZJ.html
Its from the first Core series and yours is from the second. Sandy Bridge was a big jump over Neihelm. I would just overclock your CPU some more.
If you are set on going for a bigger CPU, I would get a modern Haswell based Server motherboard and if you are limited on cash get only one Xeon CPU and get the second one later. Don't buy a nearly 4 year old system.