I think you should focus on changes that will provide bigger gains. From joncalhoun comment I heavily endorse the retargeting sugestion, but I don't think you should worry so much about AB test for now. AB test depends on some heavy and constant traffic and a more predictable knowledge of your audience behavior. I think you are too early on it to gain a lot from AB testing.

Another sugestion is assortment and marketing. I think you already have very good channels and niche, but you might exepriment a little more.

Please, read all this presentation: http://www.heavybit.com/library/video/2013-07-16-michael-dea...

For example, i would suggest you try the market for your product for imternational students. Exchange might need the exact same product, but you will have to validate it and validate the channels for it. This is an example of assortment, but you should really see the video above and develop your own ideas about to find new markets and scale a little more.

And from what I could see you are doing great. Very well done validation, distribution and website. I predict a lot of success for you.