Fried 2 USB port- what to replace on the Logic Board?

Today I did something very stupid - I attached a USB 2.0 Hub to my iMac 27" and instead of powering it with a 5V power supply, I used a 12V power supply by mistake. Result: 2 of the 3 devices that were attached to the USB-Hub have been killed (a mouse & a Mac aluminium keyboard, my HTC One luckily survived).

Furthermore, and this is the worst part, 2 of my iMac's 4 USB ports don't work anymore!

I wanted to ask if there's any professional out here who know what exactly fried on the Logic Board. If it's just some resistor(s) or rather ICs, and which ones specifically can be assumed to have made it to silicon nirvana...

If it's clear what needs to be replaced I might find somebody with the necessary skills to accomplish the task. I've got soldering skills, but obviously for this job, you need a lab with SMD-soldering capabilities etc..

I just bought a USB hub, and it works on 1 of the 2 fried USB ports. So 1 port is definitely gone. I assume it's not worth the hassle to try to fix the logic board as it might go wrong and cost lots of $$$. I advise anybody to look twice what power supply he's using before connecting it to a USB hub...