Plug it in, and see how you like the improvement. I'm going to predict you'll have great results. You must have some kind of speakers lying around, so just use those for a while. If you're not in fact in a big hurry, don't be so impatient as to split your funds between too many components, because at the lower price ranges you'll not be very happy. Next time you get $2500 or more, spend it on some decent used, full range speakers. Lots of deals available in that category.
Turntable: unless you have a lot of LPs or a lot more money than you're indicating, I say don't do it. At least not yet. Stream and play CDs, and you'll be fine.
Good luck!