This seems to be alittle late, since you've stated you bought one already but sidearms aren't really required right away so if you're on a limited budget then hold off on the sidearm in favor of a good rifle and the rest of the basic gear you need.
There are really only two choices when it comes to sidearms, AEP's (automatic electric pistol) or GBB's (gas blow back).
The problem with AEP's is they're weak fps. Small batteries mean they have little staying power as well. No blowback either, or if they do, then they're even weaker then normal.
GBB's fire hotter, last longer (or rather are much easier to refill) and, due to blowback, are much cooler. The only reason pretty much anyone gets a AEP is to have a sidearm for the colder months. The only way to get a good performance AEP is if you start going into the borderline smg area like mp7's or mp5k's.
A good AEP is going to be about the same cost as a good GBB and still won't have as good a performance as even a cheap GBB.
The KJW 1911 is a great gun, I have one myself (the 1911a1 model). I see you stated you bought a full metal KJW 1911 and I also see you're not age verified, which means you didn't get it through us. I hope you didn't order it from a site outside of Canada, cause if you did you're very unlikely to get it. Full black guns are prohibited by Canadian customs and will be seized if customs catches it.
A couple of things to be aware of with that gun though: The single stack mags are alittle more troublesome doublestack ones. Since BB's are tiny compared to bullets, a single stack mag holds as many rounds as a double stack mag. The problem is the gas reservoir is substantially smaller. With a ABS slide you can almost always get through a single mag's worth of BB's but not much more. With a metal slide (which the KJW 1911 has) you're reduced to no more then 15 rounds, maybe 20 on a hot day with slow firing.
Another thing is mag reliability. Alot of people report KJW mags are finicky. I've owned two different KJW pistols and have personally never had a problem, but I baby my mags anyway. There's an easy out for that with a KJW 1911 (at least the 1911a1) which is TM 1911 mags fit even better then the original KJW mags, and there's no questions about TM reliability.
I don't know how much you know about GBB's, so I'll cover fueling them as well. Offical documentation usually states that GBB's run off of Green Gas. But the thing they don't want you to know is Green Gas is just propane, mixed with silicone oil, stored in an unsafe container, and marked up in price by like three or four hundred precent. If you get a GBB that runs off of Green Gas, and they pretty much all do now-a-days, then just get an Airsoft Inovations propane adapter for about $20 (which includes a small bottle of silicone oil) and a can of coleman's propane from Canadian Tire and you're good to go.