First off, welcome! Glad you liked the mod, we are always looking for feedback. As for your programming skills, that is definitely not the story, you can totally contribute to this mod if you are an artist (mapping, modelling, 2D stuff) or are into sound fx.
Anyway, as for the game controller... that depends on who made your controller. Some let you do multiple inputs at the same time, some don't (in a game). Also, Source's support for game controllers isn't entirely the best and that is out of our hands for the most part. I am not sure we can offer you much more help then this, update your drivers and check out your config program for your controller.