What do you mean by "balance"? Why do you want it? Why didn't you want it before? Are you taking the longterm view, or are you concerned about week-to-week (or year-to-year) fluctuations? Knowing yourself is a big part of any investment decision.

Bonds are now quite high-priced and low-yielding (except junk bonds, but that's a whole different story). If you buy bonds now, you will lose principal when rates go up. If you can keep on adding funds to your bond portfolio during the ups and downs, though, that's not a big deal. I wouldn't pour all my funds in right now.

The point of a balanced fund is to buy bonds when they're cheap relative to stocks, and sell them when they're expensive relative to stocks.

the fund I'm in does not allow for switching in and out of funds at the drop of a hat
Good for them! But if you realize you've made a mistake, and your thinking is sound, you should switch out of the mistake at the earliest opportunity (as long as you have something better to switch into). Don't dawdle around just for "patience's" sake.