How do you have the fans setup in your case? That case looks like it could be the main problem as its airflow is likely going to be a little wonky no matter what you do. According to LL, the two fans that come installed are used to input cool air, but nothing is dedicated to exhausting the warm air inside the case. You added a fan to the vent directly over the cpu, swell, but is it blowing cool air in or is it exhausting? How did you install your psu? Is it setup so that it draws air in from the vent on the side of the case where it would be located, or did you install the psu so that it pulls air from inside the case and acts as an exhaust? The sensible thing to do would be to install it so that it has a source of cool, fresh air from outside the case, but on LL's website they show the other configuration. It's always possible that the problem is that the stock hsf hasn't been installed correctly, but I think you also need to look at airflow in your case a little more closely.
Not knowing what you've done, I'll just hazard a guess as to what would work best in your case (I'm no expert on these matters, mind you). Orient the psu so that it's drawing fresh air from the side of the case (unless it's so long that it doesn't line up with the vent). Install an extra fan in the vent next to psu and orient it so it brings cool air in to the case (if it were me, I'd remove all of the hard drive cages that will empede airflow that you aren't using). If you aren't using any optical drives, and that cage comes out, I'd remove that, too. Next, since you're using the stock Intel top down hsf, I'd use the vent above the cpu to blow air into the case. Then I'd take the two fans on the side of the case by the cpu and flip them around so that they're exhausting hot air. You could always fool around with the fans to see what works best, but that would be my first stab at getting reasonable thermals. LL shows the two case fans blowing air clean through the case, and that looks great, but that big old 6950 in the middle is going to disrupt airflow (and put out a decent amount of heat) and, assuming it's installed correctly, the psu isn't going to work as an exhaust for the case air. Anyhow, I think that if you just took the two fans already installed in the case and use them as exhausts your cpu temps would go down considerably.
As other folks here have suggested, a thirty party cooler wouldn't hurt, but it may not be necessary if you get your airflow working well. If you do go with a new hsf, take some measurements as I'm not sure a tower like the 212 will fit in there.