First off, that is a nice car! I am partial to older, big Fords but yours is very cool.
You have to decide for yourself whether you can part with it. I am facing the same with 2 460 Mustangs in my garage. I keep thinking if I wasn't putting money into 2 of them and just into one, how much better would the one be? Just my line of thinking.
As far as the value of your car, I believe with what it is and what part of the country you are in says the car's worth might surprise you. I looked on all the craigslists in your area and ebay and found that just like everywhere else, classic car prices are going through the roof. Add to that the the convertible factor. I wont actually take a specific guess on it's value but multiple thousands is a good starting point.
I would recommend you research all the classic car ads you can find to get an idea of what today's value is. The ridiculous asking prices are actually driving market values up! I find NADA is always a little high IMHO by about 33%+. craigslist and eBay are goodplaces to start. eBay has several right now.
I spend a good chunk of my life buried in classic car stuff here on the west coast and it's gettin crazy out there! The east should be even better for you.
I hope this helps!
'67 466 / C6 / 9" Mustang Coupe