+1 on the lemonade. Davin hit the nail on the head here in terms of setting yourself apart. You need to give your visitors a reason to visit again. Your traffic isn't registering and returning probably because it lacks the content they desire, or it's serving the content they are getting elsewhere and potentially in a better form. Unfortunately, with the community you're trying to build, there are so many cookie-cutter ones already out there that strive to be the biggest and the best and have just flooded the web. I suggest taking a step back and asking yourself what you can offer to set yourself apart. Put yourself in the perspective of your target demographic and ask yourself "What do I want to be available to me in this community? What will hold me as an active member?". Jot down your thoughts and slowly work at getting these available to your member base.
This is a tough one to answer without seeing your site first-hand. I'd say in your situation as I understand it, no. As I touched up on previously, your visitors are not registering nor returning so they simply aren't liking what they're seeing. You may see a spike in new registrations, but once your members gain access and find that your site is not offering the content they are after, they simply won't return.
By doing this you may gain registrations, but you will lack the recurring returns.