Wow thanks for the heads up on this. I haven't been able to afford them on any campaigns yet, but it's good to know that the community is looking out for me.
To finish strong, and assuming you've tapped out your facebook ad budget. I'd say you'll want to do a pr campaign, getting a few articles before your campaign closes is a great way to finish strong.
It was so important that I began growing my email list about 3 months in advance of my campaigns. The best way to do this is to run facebook ads from what I have seen it works quite well.
Gadget flow is great. I'd also recommend Braniacs from Mars, Crowdfunding PR, and Krowdster as well. They're hit or miss, but sometimes they'll produce a great boost.