I have an Applied Bank Secured Gold Card and I would like to know should I keep it?

I had been with them since November 2008. I been making a few small purchases every other month on the card as well as making on time payments. I have a $50 annual fee coming up, and they given me an option to cancel the card to avoid the fee by writing to them for a request for card termination. They also told me the card won't convert to unsecured because they don't no longer offer unsecured credit cards anymore. Does anyone think I should cancel this card since the annual fee is approaching and they won't convert the card to unsecured or should I go to another credit card company to build more credit and get a lower annual fee with another secured card? My highest credit score is 567. Any suggestions? Thanks.