Jesse, if it were me I'd use the Circular Marquee tool (press the M button (shift + M if you're stuck on the rectangular one), then I'd use it to select the first eye, I'd then hold the SHIFT button down to select the second eye. (only select the red part) At this point you have a selection of just the red parts of both eyes.
Then I'd feather the selection just a little bit (Ctrl+Alt+D), maybe 2 or 3 or 5 pixels (maybe a lot more depending on how big your image size is) - if that's the actual size of the picture, I'd think 3 would do it.
Once that's done, I'd hit Ctrl+U to adjust the Hue/Saturation. Slide the top slider (saturation) around until they look to be the right shade. You can adjust brightness and saturation here too. Make sure the 'preview' button his checked so you can see what you're doing as you do it.
The key is getting the selection right.