replace cd player and computer speakers

I reiterate my above recommendation that will do what you’re looking for and strongly encourage you to get away from cheap, self-powered speakers.  Another thing to consider is speaker placement in your room.  Pulling speakers out another foot or more from the back wall can do wonders for clearing up sound and dramatically improve imaging and soundstage as well. 

and phono section/tt/cartridge ?: that does not exaggerate intraband  surface noise and has good tracking performance? .

Really depends on how serious you are about vinyl. The Decco has a decent MM phono input, and the Pro-Ject Debut Carbon is a good budget table that comes with tonearm and cartridge and is worth a look. I can’t comment on relative performance regarding tracking and surface noise, and you’ll get better recommendations on that in the “Turntables” forum. Also, it’s very helpful for someone trying to make a recommendation to have a dollar amount for budget purposes. Just saying you want the improvements to justify the increased cost doesn’t really help much, especially on this site.