Re: photography for dummies…
why would you need a zoom lens at a wedding man? 
what you have is a decent all-purpose lens. get a good 50mm fixed too, and you’ll have enough glass to shoot some good wedding shots. if you want, you could get a decent external flash as well.
but most importantly, learn how to work your cam. what focal lengths for what shots, all about apertures and shutter speed. otherwise it is just another point and shoot cam, and the results will be similar.
there are plenty of online photography tutorials. or you could buy a book on it. good luck.