Hey man, it seems like your in a bit of a tough situation so let me try and shed some light. From growing 1-2 small plants you really aren't going to have that much of a smell unless your growing some really dank stuff. I think you would be fine just using a little spray and a fan to keep some fresh air in your room and open a window or something. But if you are really worried about it do look into some carbon filters or something like that. They are easy and can be placed inside the grow box, or what not.
Now go look on
www.google.com and search for some good guides at how to make them. No one on here is going to know how to make a really good one, so go find some guide that the author actually took time to explain it and post pictures of all of it. This are simple and cheap, so shouldn't be a problem. You can pick up the active carbon stuff at your local pet store and then the rest of the supplies would come from your hardware store.
Also stuff that will help make your yield as big as you can get it is lights, try and get some good lights, and also make sure you put reflective stuff around your PC case so you can maximize your lights and everything.
Best of luck...