Red Triangle - Dealer or My regular mechanic & should I look for new car?

This past weekend, the red triangle popped up on my dash intermittently, about 3 times over two days. It would flash and disappear. I didn't see any additional corresponding information on the information panel or control panel. My 2005 Prius is at 163K miles, and looking through other threads it seems like this is probably indicating the inverter coolant pump needs to be replaced.

Is this something that should be taken to the dealer, or could I take it to my regular mechanic? Or, could this be something different than the inverter coolant pump?

I'm also wondering if it might be time to look for a new (to me) car. Since October I've had to replace the 12V battery, wheel bearings, front and rear brakes, and had to replace the hood latch that had rusted shut. I do have to park my car outside year-round in the Northeast, so not all of this is surprising given it's at 163K miles. However, I'm curious from other owners if these repairs seem in line with the norm or if I should consider looking at another car.

Up until this past October, it's been an outstanding car with only routine maintenance required, which is what I've always loved about it. But if it's going to be a significant repair every few months from now on, it may be time to start looking.