Best Minecraft Video Card?

So, I've been recently looking for a graphics card solely to up my FPS for my Minecraft. The problem is, I don't know much about them so that's why I came here!

I have tried Optifine. I average around 60-80 FPS and I know that I can get more than that.
Ya see, 60-80 FPS wouldn't bother me at all, but I was looking to record some YouTube videos.
I was recording with a my pretty legit program and I noticed that my FPS level wasn't satisfactory.
I was also looking to run some High quality Seus Shader Packs without getting only 5 FPS._.
So, since these occurrences, I have been looking for a decent video card.

If this helps, I'm also running a late 2010 iMac.
(For the love of Notch don't tell me I need a new computer, this silver 25 pound behemoth is my only child.)

My price range would be maxed at $215-(ish).

Thanks so much for any of your help!

I bet I sound like some squeaker 9 year old writing this post…

First, you can't upgrade a Mac. The components are soldered into the motherboard and can't be replaced. Even if you could, you would need to upgrade much more than the graphics card. How do you even know its your graphics card thats limiting your performance and not your central processing unit or random access memory? Also, power supplies are JUST powerful enough to run the components in the system, and by upgrading to a more powerful graphics card you would also need a new power supply which you would have to reconnect to the motherboard (24 pin), central processing unit (4 pin) and graphics processing unit (6 or 6+2 pin) PLUS the case on/off switch, case restart button, case fans, etc.)

Your best bet is just to buy a PS3 or Xbox 360 and get Minecraft on that otherwise a decent premade desktop would cost you ~$500.

"If this helps, I'm also running a late 2010 iMac. "

Sorry, you can't upgrade the video card on that unit. It's the price you pay for the thin stylish design.