Will this graphics card work with my computer?

I have a Dell Optiplex 745 using the ATI Radeon 2400 XT Pro but I want a better graphics card. I currently get about 40-80 (max 85) FPS on games like minecraft. I really want to know if the ATI Radeon HD 3470 Will work based on if it will fit/work with my computer. I don't know how to check either. Also, if you know of any other cards that work very very well, especially with minecraft, then please let me know by leaving a suggestion. Thanks!!