To XJessicAX: congratulations, your scores are high enough for you to get into a good program. goodluck
To ramana2004: I have some expereiences with PowerPrep that you may want to know.
1. PowerPrep is very similar to the real test. the picture, interface of program, and the voice, and especially, the difficult level, all are very similar. Try to practice with PP as much as possible , you will get more familiar and be calm with your real test.
2. for my case, my score on the CBT is 263 without TWE. and my scores with PP ranged from 250 to 273. So the real test is very close to the simulated test.
3. If you want to improve your listening score, the only way is to practice as much as possible.
Good luck