Deciding on a phono preamp

I have a Thorens TD160b MKII turntable with an Infinity Black Widow tonearm and a Grado Green cartridge. I think that I have had the turntable and tonearm since the early 80"s and the cardtidge since the late 90"s. I can't remember ever using this turntable let alone with any kind of a decent system so I have no idea what it actually sounds like or is capable of.

I now have a fairly decent solid state system that I am considering connecting it into however it lacks a phono input... don't they all now.

Preamp - Anthem AVM-2
Amp ATI 2000 series (200wpc)
Speakers Energy 2.3i
Sub 15" 500 watt sub (kind of home made).
Blue truth interconnects
Flexegy-6 River wire to the speakers

I am trying to get a feel for how much I should invest in the phono preamp.

I was contemplating just getting a preamp in the $100-$200 range but if the TT and arm are worth it I was thinking of moving up to something like the Pro-ject tube preamp and then getting another cartridge.

Any thoughs??