I have owned the SW65 and it was a good practice amp. No problems with at all in the year and a half that I owned it. Just did not have enough juice for even a small gig with a drummer.
The SW100 isn't going to help you much. It's louder then the SW65 but it's still only 100 watts. You can put the extention cab on it and it will give you 145 watts. Still not that much. The extra speaker surface area of the extention cab will help you with volume but at 145 watts you will have very little power in reserve.
The Ibanez amps are budget oriented practice amps. You could do small gigs with a SW65 or 100 with PA support and use it as a monitor if you plan on gigging but it will be limited in that capacity as well. I tried that with my SW65 and it ran out of beans quickly.
If I were you I would look at a used head and a 2 X 10 or cabinet. Good used gear would be Peavey, Ampeg, Avatar, Carvin and GK. Use your SW65 as a practice amp.