too much to answer on the wrong section of the forum, but i can answer one thing out of all you posted.
is my current setup worth upgrading to get better performance?
no, definitely not even for another 1.5 years or a lil longer.
for info about GPU upgrade ONLY cos of BF3 - read this
seriously with that matrix - you need not look any further than under your nose...or next to it if that rig is next to you