Rock Band 2/3 Set up for Wii U

So me and my wife want to play Rock Band 2/3/Green Day/Beatles for Wii through our new Wii U.

Where is a good place that still sells all the gear (2 guitar, 1 drums, 1 keyboard) for cheap as well as the software?

If the PRO controllers are at good prices I might be interested in them.

Play N Trade and Craigslist are your best bet.
Also if you have a 360 I highly suggest getting Rock Band on that.
PS3 would be 2nd choice.

As one of the few fellow Rock Band Wii players, I can say that most instruments are not easy to find. I had to go on e-bay for my RB2 drums. The easiest will be the microphone, since that uses any USB microphone and I found plenty of those any nearly every second-hand store I went to.
Also, make sure that anything you do find has the right dongle. Not sure if you can replace those from Mad Catz or not.