For years I considered my Roth principle my EF, college help, etc because the fund could grow, but after 5 yrs you can take out the principle for any reason, I did use Vanguard Index funds. So this won't work because you do not have 5 yrs and I, too, would not take risk with money you need in 2 yrs.
I've never done this, but what about putting it in CDs? I've read in finance books that explained how to ladder them time wise but honestly I do not recall because I never plan to use those. At least you'd get a tiny return and be totally safe.
If you are getting interested in investing, you might want to try one of John Bogle's books, he started Vanguard.