Does anyone have suggestions for upgrades on my old 14 that I bought?

I am new to cats but have lots of windsurfing racing, etc. experience.

What about a spinnaker?

The upgrade that I will ultimately get is a 16 or 18, however until then..

Not sure what your boat might need, but I wouldn't get too carried away with spending money on the 14. It all depends on how you will be sailing. If you are thinking about taking others out to sail with you, save your money for a bigger boat.
Jack