Yep, get that out of there and replace it with 50/50 of the yellow. Green and Red shouldn't mix. You might even consider taking it to a shop and having them flush the system good just to make sure you get as much of that mixture out as possible. Make sure they have one of those machines that actually sucks the coolant out of the block. I can't remember what mixing the two does to the engine but I do know it's nothing good.
Hell, I still run yellow just to be on the safe side.
See...told you it never ends. Look at it this way, you'll be getting more of that gunk out of your system. LOL
