To build on what both guys have said,

Keep in mind that for every dime size (for example) rust hole you see, the actual amount of damage is the size of a silver dollar once you get the paint off. I'm sure there are lower quarter, and/or wheel opening sections available. You want to check around because different sources will likely have varying degrees of accuracy in their duplication of the factory profile. Nothing more frustrating than trying to get an ill fitting patch panel to fit and look right, sometimes more work than any money you might have saved trying to save a buck or two. And once you cut away the the outter panel you'll see you have rust damage on the inner panels, e.g. wheel house, trunk floor extentions, etc.

Welding a long seam joining the patch panel to the existing remainder of the quarter is not a job for a rookie. Distortion is highly likely. If you want to do it yourself and it's your first experience you may be wise to have the cutting, fitting, and welding done by an experienced body man, maybe working on the side so you can watch and learn, and then get your learning curve on the filling and priming which is more forgiving.