Where to begin?
If you're gonna be a DJ, a mixer would be a good idea, but then you're doing it on your laptop, so goodbye super control and just live with what it gives you. At your level, that should be fine though.
You want 1 DJ light. How about an Electra 250? Costs around $100. There are loads of options. Maybe a Vertigo? Mine cost me less than $150, I remember that. You need to avoid any DMX fixtures for two reasons: They are going to cost more, but more importantly, you're going to want a DMX controller of some sort, which is going to add a lot of up front costs.
Hooking your laptop up to a surround sound system, eh? Got a line out or a headphone out? If it's a headphone out, you're going to want to put an impedance matching transformer in there to convert it to a line level(or preferably, mic level), and then probably into some sort of device(such as a mixer that probably has phantom power and XLR inputs). THEN out from that mixer into your little surround sound system. Oh, don't worry about comb filtering, I'm sure you're not concerned about that sort of thing. Unless your audio source is surround, it's not worth it. Even if you emulate a 5.1 matrix from your 2-channel source, trust me when I say this: it ain't gonna sound as good as just going 2-channel or even 2.1(you can use the LFE cut-off to process low frequencies to your sub).
Then, your next step is the wood floor and the bar taps and you can be Pimp-Master-Carlos, the Un-DJ DJ. Goldfish in boots 100% optional, but pimp cane is not!
Just messing with you there on that last part.
Good argument for the Vertigo: Non-intel, sound active, moves via sound and I think the latest ones can run all night. Not super hard on pulling power from the wall and the motors aren't too noisy in operation and it doesn't put crap on the AC either. And it meets your budgetting.
Also, check out other "high-tech effects" from ADJ, that's the area you want to look in for the time being.
Now, should you do end up going with the Vertigo, you can always put it on a dimmer or switching pack controller via a DMX controller of some sort. The Vertigo is a very popular fixture, a good crowd pleaser and it can "grow" with your rig as you expand.
Have fun, don't spend too much money.