f1.8 lens for the SX40

I'm about to get a Canon SX40. I was reading about every single topic but still have some questions. One of them is: is it possible to add an f1.8 lens to the SX40 (to achive photos with nore blur)? I thought it may be added with an adapter but someone at the store told me it can't be added. If not, is there any lens that can be added to chive these kind of photos - to get more aperture than the 2.7 of the camera?

Thanks!!!