And my opinion...
Definitely a better cart. It will make a much bigger improvement than cabling. It's hard to beat an Audio Technica OC-9/II if you can get a step-up device or phono stage that can handle it. If not, have a look at a Denon DL-110 HO MC cart. I haven't heard it but others have and seem to like it.
I'd call Keith Herron to see if he can help you with cables. I'm using his cables and they seem very good. And they are very reasonably priced.