Beginners question. Axiom + Quad-Capture + Sonar X1 LE

Background, short: My mothers birthday is coming up in the summer. I wish to perform a small show. I shall buy the violin, I know how to play. I wish also to create the background music. Not so advanced, just some other instruments playing in the background... *** I've looked at M-Audio Axiom 61. I got help at the salesperson at Thomann telling me, the computer is probably too slow and I need the (more simple) Fast Track or Roland Quad-Capture. My friend used to be a professional musician. He tells me, it is so difficult to create music... and this makes me even more ready to try! I think, it works for any one else, it's just a matter of time, will and interest. I'm a programmer in my profession. I have many questions. First, how do I connect all these things? This is my impression: Axiom --> USB --> computer --> USB --> Quad-Capture --> DIN (line out) Is this correct?