Need better frame rates based on my current setup.

Hi, I'm a huge fan of the game, Total War: Shogun 2, and would like to start making high quality fan videos in 1080p on Youtube. Currently, on full settings I'm getting 30 fps with DirectX 11 enabled in Ultra Settings with every graphic option enabled but once I turn on Fraps and start recording it drops way below 10 fps, often unpleasant to even view.

My first build and current setup:

Case: Antec 900-II
Motherboard: ASUS P6X58D-E
CPU: i7 930 @ 2.93 Ghz

The best I've done so far is 3.67 Ghz but I never had the chance to test it with DirectX 11 because by the time Creative Assembly released DirectX 11 for this game, my PSU was already dead.
CPU Cooler: Thermalright True 120

At 3.67 Ghz, this heatsink keeps my CPU cores at 69C under load. I will consider overclocking to 4.0 Ghz but will have to wait for the new PSU, since I am currently using a backup PSU (RF-900WPS)
GPU: Gigabyte GTX 470
RAM: G.Skill 6GB DDR3 2000
PSU: Corsair TX950

I was using this, but am currently using my backup PSU. RF-900WPS.

http://www.youtube.com/watch?v=32qFX3Qo4AE = My goal. I would like to make videos similar to this one, of its quality and in its frame rates (or at least do the best I can in coming close to it).

What I consider replacing:

1. PSU, the Corsair is dead, I have to warranty it but instead of waiting for the replacement I rather just get a new one, modular. I plan to just sell the replacement when I get it. I am not sure if my backup PSU, the Rocketfish 900W will be sufficient for the SLI setup I plan to use.
2. GPU, I plan on getting another GTX 470 and going SLI and will even consider recommendations of other GPUs. Financially it would be more wise to just get another GTX 470 but I am not sure if two would be sufficient in reaching my goals.

Any advice would be appreciated, thanks.