Contact infinity. I had some tweeters blow on some beta 50s and they replaced them under warranty free of charge. they mailed em and I installed em. I beleive the primus line has a 5 year warranty.
if that is not an option try partsexpress.com, they can recommend a replacement that is similiar to what you have.
When replacing a tweeter, there are are about 6 different variables that ALL must be matched precisely to get a suitable replacement.
The bottom line is that only the original manufacturer is going to know everything that is needed to supply a replacement that will restore the speaker to correct operation.
Call technical support at the manufacturer and work with them.
I've abused Primus speakers and made them good as new with new drivers that I ordered from Infiinity. The prices were fair and the delivery was reasonable.