Got PCI slots? Any old thing should work.
This is, of course, just a temporary measure while you work with your insurance company to get your damaged computer replaced. Homeowner's insurance. You got it, right? Time to use it.
I've seen computer equipment that was not immediately fried fail prematurely after electrical damage like that, so you do want to replace it, especially if a motherboard component like the NIC has been damaged.
Second: what's the best way to verify if specific hardware is fried beyond repair?
Take it to a computer service place (in your case, someone familiar with Macs), and have them look at it and write something up for insurance. I do this all the time after major storms. I've never yet had an insurance company balk at paying for a replacement. Just turn in the tech's bill to insurance. The expense of that will be applicable toward the insurance deductable.
If you have a decent surge protector|UPS, you probably also have an equipment protection warranty. The downside of that is that if you have your stuff plugged into anything at all other than that manufacturer's stuff, it will get denied. No having a Tripp Lite surge protector plugged into an APC UPS, for example.
I have no DSL connection anymore (the service works but neither wireless nor LAN work).
Fried dsl modem and router. And your Mac's ethernet -- imagine that. :-).
