Extra money advice

I'm currently in a good situation with my job where I have extra money in savings and will continue to be able to save for about another year until I look to buy a house. I feel like it's no good to have it all just sitting in savings. My fiance has some in Vanguard's mutual fund, so I don't know if I should stay away from that and go with something else. I am obviously no financial guru. Any advice would be appreciated.