You really need to do better research, your statement that you don't want to learn about the stock market is a good way to guarantee that you never really make the kinds of returns you should. If there was a reliable, easy no-knowledge way to grow your investments, people would already be doing that.
A better option may be to look at some money market accounts. We have accounts with Ford Motor Credit and GMAC (now Ally). Check out http://www.ally.com/money-market-account/index.html it's not going to be the highest possible return rate, but there are no fees for "investing" your money, the funds are liquid, and as you get to higher balances you can get better returns. This is where we keep our "accessible" funds (low 6 figures).
Also, I'm not sure how much you're contributing to your 401K, but it may be worth bumping that up as well. You should probably at least be doing 10% of salary.
High-yield CDs would also be something to look at.
In short, for the dollars you're talking about, I would NOT consider anything that charged a transaction or maintenance fee, it would eat up any potential earnings.