i know this already, but i figured i would get the graphics card upgrade out of the way first bc buying a new psu didnt seem as hard a task
Now, with a new PSU, you'll be able to use it then let it sit there. And I would be afraid if your current PSU fails on your computer and take some components with it.
Also, getting another video card in the $100 range wouldn't give you much of a boost from a 7500. Use that $100 for a new PSU.