MSI GT 710 Compatibility Questions

[Sup3rM4r10Br0s]

I'm currently considering on buying the MSI GT 710 Low-profile graphics card for my aging Dell Inspiron 660s, but I have several questions
1. Will it PHYSICALLY fit in the PCI Expansion opening (as the 660s uses a smaller opening than the usual PCI expansion slot) ?
2. The requirements say it needs 300W of power, but the 660s only supplies 220W. Is there any way I can upgrade the power supply?
3. If you think I'm wasting my time on the 710, is there a better graphics card that's less than $50?

Additional help is welcome.