Hi Chevymetal – I agree with Bruce. You don't really need the Beachtek. That said, you may still want to get one.
I have the TM900 also, and it is a great camera – but the challenge is the quality of the camcorder's preamps, not just the quality of your external mic. Yes, you'll be able to connect the G3 directly to the camera with the included XLR to 3.5mm jack , but you' ll still be stuck with the TM900's noisy preamps. I recommend getting something like the Beachtek. For $179 at Amazon (as of this post), it's a good investment.
Good luck with your audio upgrade!