Quick answer, probably not. it depends how close people are to the booth graphic. if it's always going to be 10 feet away from the viewer, well, maybe.

Most vendors tell you that 100 dpi is good enough for booth graphics, meaning you can easily get your graphic to be 3x the size it is now and look okay. So, at 33" x 51" you should be okay, however, everything after that has the potential of looking a little grainy and blurry. Some people would say that Photoshop's resizing will comfortably allow you to double an image in size without hurting the quality, so, maybe 66" x 102" ...

With all of that being said, I've used similar quality photos on roughly a 10' booth and they look okay. They're grainy, but i didn't mind that they were grainy because they aided what I was trying to do visually.

Not recommended. Even with Fractals you will still get graininess. It all depends on the print device and the fabric. If you go large solvent like a Vutek you can take the resolution down to about 45dpi at final. It will be grainy up close but not pixellated. If you are truly talking fabric (and not the graphic design community's concept of "scrim" ie vinyl), the fabric tends to allow the ink to feather just a little to compensate for some of pixellizing. Don't get me wrong and think the ink bleeds together. It is something you won't see with the naked eye unless you know what you are looking for.

Get a full res proof of a section before you commit.

If you have Photoshop CS, you can now resize stuff without getting grain or bluriness..

i wrote a brief Tut on how to do it on the GDF, but I think its dissapeared now, it had something to do with increasing your photo by only 10%, making an action of it, and doing that as many times as you can until you get your desired dimensions.

D-Frag, that's an old trick. It's been around for years.
While PSCS does have a better upsampling generator, I'm not sure it's any better than using Fractals.