Get to the shop asap so the contaminants aren't just sitting in the trans potentially corroding the transmission internals.
Not really qualified to give any advice on this, but have been following this thread and the above is bothering me. If the transmission fluid is showing signs of contamination wouldn't you want to get it out of there immediately or sooner? Seems like leaving it in until you change the radiator is asking for damage that you might be able to avoid if you get it flushed.