98 Legacy AC woes--help!

It started with car's AC losing effectiveness plus a sorta gasping sound at times from under the dash when the unit was running poorly.

Now, there's quite a noteworthy clanky//tinny sound from engine when the AC unit is on and the fan goes off and on. I wonder if it's the clutch on AC compressor---now this next point may be irrelevant, but there sems to be some redish dust accumulating on the surfaces beneath the AC unit. Hmmm....It does sound expensive.

Here's my 2 questions.

1.Am I better off with a reputable independent repair shop fixing it--or should I go to dealer---as they have experience and expertice???

2. Any idea what balpark price is for such a repair??? Can this be a DIY job??