Ok---> Firstly a little help for you on the ohms bit. Check out this link.
http://www.eatel.net/~amptech/elecdisc/ohm.htm
Basically ohms are the DC resistance of the speakers Voice Coil.
Typically Car Audio Speakers are rated anywhere between 1ohm and 12ohms. To measure the ohm load of your speakers you will need a multi-meter.
place the multi-meter on the ohms setting (symbol looks like a small set of headphones/upsidown horseshoe) Take the posative lead of the multi-meter and connect it to the posative terminal on the speaker, Take the negative lead of the multi-meter and connect it to the negative terminal of the speaker. You will recieve a read out on the screen of the multi-meter of the speakers ohms or impedence.
Most of the L7's are usually Dual 2 ohms, Dual 4 ohms, Dual 8ohms, meaning that there are 2 voice coils within the speaker. Both voice coils will have matching impedence (ohms). This allows greater flexibility in wiring options (bridging).
Just a brief overview of ohms- again- check out the link above, it contains more in depth information.
AS for your subwoofer and Amplifier choice-
Yes the bd1000.1 will handle 2 ohms fine, it can take the heat even a little more below that ohm load as well. Your sub will be quite happy with that amplifier.
Take it easy,
-zane