Took my 2005 Audi A4 in to the dealership for an oil change and to have a few issues corrected. When I was driving a few days ago I heard a pop w/ the speakers and they turned off. At the same time the CD player showed an error that said "error 3"

A while later heard the pop again and the speakers turned on. The speakers have gone from on to off a few times. They are currently on and have been for a day or so.

Anyhow, the dealership told me that the problem is that my antena booster in broken and I need a new one. They said the cost for parts/labor to replace it is $450. They said the part itself is over $300 and that the replacement doesn't require much labor.

My questions are:

1. Can I find an antena booster cheaper anywhere else? Can I get one from a junk yard?

2. Is it difficult to install? I am not very handy, so if it is more then a few minutes, I can take it to a local shop (not the audi dealership) to install.

Any help is appreciated.