What do I need to play The Sims 3 Pets + CC & Mods with maxed settings?

[Lax'l Cho-ja]

[FONT=Trebuchet MS][LEFT][FONT=Trebuchet MS]What do I need in order to play TS3 Pets + CC & Mods with maxed settings? [/FONT][/LEFT]
[LEFT][FONT=Trebuchet MS]Below is my current system. [/FONT][/LEFT]
[LEFT][FONT=Trebuchet MS]The Sims is currently unplayable on my comp. It takes forever to load, and when it finally does the graphics are extremely bad (no matter how high or low I have the settings), and when I go into buy mode it freezes. [/FONT][/LEFT]
[LEFT][FONT=Trebuchet MS]Sorry for being so n00bish. [/FONT][/LEFT]
[LEFT][FONT=Trebuchet MS]Thanks in advance for your help. [/FONT][/LEFT]
[LEFT][FONT=Trebuchet MS]- S [/FONT][/LEFT]

[LEFT][FONT=Trebuchet MS]Windows Edition: Windows 7 Professional [/FONT][/LEFT]
[LEFT][FONT=Trebuchet MS]Processor: Intel(R) Core(TM) i5 CPU 750 @ 2.67 GHz [/FONT][/LEFT]
[LEFT][FONT=Trebuchet MS]Installed Memory (RAM): 4.00 GB [/FONT][/LEFT]
[LEFT][FONT=Trebuchet MS]System Type 64-bit Operating System [/FONT][/LEFT]
[LEFT][FONT=Trebuchet MS]Graphics Card: NVIDIA GeForce GTX 275[/FONT][/LEFT][/FONT]