If someone could give me a short explanation of how power ratings and resistance coincide, that would be awesome.
I'll just throw out a general explanation and hope this helps clear it up a little.
Scenario:
Dual Voice Coil Sub (what you just purchased)
1000 watt monobloc amp (1000w x 1 channel)
Most amps are rated at watts per channel given a specific resistance. Say this amp is 1000w x 1 channel at 2 ohms. This means at 4 ohms it will only output ~500 and at 8 ohms somewhere in the range of 250, again the exact output will vary amp to amp. So you have these options:
Wire in series, this will give you a total of 8 ohms, 4 ohms per voice coil (pretty standard) added together. Meaning the sub will get 250 to 300 watts from the 1000w amp.
Wire in parallel, basically wire the positives from each voice coil together then run to the amp, then the negatives and do the same. This will divide the resistance, giving us 2 ohms therefore 1000w from this amp.
Now when it comes to amps and subs there are two wattages you have to pay attention to, peak and RMS (route mean squared). Peak is how much either the amp can output, or the sub can handle for a short time. RMS is the would it puts out or can handle as a standard. When you look at spec sheets it will generally say the power rating and either RMS or Max. So some amps may say 1000w, but that may only be peak. RMS is the more important number, peak is essentially worthless. You want an amp with an RMS output that matches your sub. This will give you (generally, again some amps and subs just suck) the best sound quality and longevity out of both.
Sorry this is just a general run down of how this stuff works.
What kind of music do you listen to? Do you like sound quality or sound pressure?
I personally like Alpine and JL Audio gear. Alpine is a fair amount cheaper though. They both offer reliability and very good sound quality. Check this amp out:
http://www.alpine-usa.com/US-en/products/product.php?model=MRP-M500
It's rated at 500w x 1 at 2 ohms at 14.4v where your sub is rated at 380w RMS. Since no cars actually run a 14.4v electrical system that 500w rating is a bit inflated and this should work just fine. It's just one option though, what kind of price range are you looking at?
For more of an explanation, JL Audio has a good write up on wiring to get a certain resistance:
http://mobile.jlaudio.com/support_pages.php?page_id=161
EDIT: D*mn this started as just a short explanation. I realized you're about 3 hours from me. If you plan on putting a whole system in I'd be glad to come down and help out, I've been doing this for a few years now.