I definitely would not dump the beer just yet. You've put too much time and money into it. I had a similar problem with a hefeweizen recently. I let it warm up, added a little yeast, and it cleaned up very nicely. I also left it in the keg to do it, then gently transferred to a new keg afterwards by hooking the two beer lines together. By keeping it in the sealed keg, I didn't lose the carbonation.