You can change the frame rate to whatever you'd like in After Effects but not in Premiere Pro. Here are the available frame rates for Premiere Pro:
If you plan on editing you're animation in Premiere Pro, I would re-render it out of Flash to one of the standard frame rates listed above, or so that it matches the rest of your footage. 33fps is not a standard that I know of, but if you absolutely need your output to be in this format, I would reccomend doing your editing in After Effects. If you're just piecing together clips and making slight duration adjustments without making a lot of cuts, then an NLE like Premiere Pro might not be needed and After Effects should work fine to edit your clips together. However, After Effects works very differently than Premiere Pro so there will be a learning curve.
For 33fps footage, you can conform its frame rate to 29.97 in AE in the Interpret Footage settings, then render it out in a 29.97 comp. Very easy.
Now, if altering the speed of the clip -- which is what happens when you conform the frame rate -- will result in mayhem, anarchy and the end of life as we know it, conforming isn't recommended.
But if you don't mind that the footage slows down just a tiny bit, you're all set.