I found the nvidia geforce gt 610 but i need to upgrade my power supply
so what do I need to get for my pc to up the power supply.
Newegg has a really handy power supply calculator. Just google 'Newegg power supply calculator'.
It'll give you the exact wattage your system is and then you can go shop for a power supply with similar wattage. In order to fill out the power supply calculator, you need to have pretty basic knowledge of what hardware your PC has. If you don't really know much about it, you can google your PC and chances are there will be a site that has all your PC specs.
And one more thing, always get a power supply that's a little more powerful than what the calculator says. For example, if it says you need a 450w power supply, get a 500w power supply.