That won't cue her in to using the bell herself. I described it in detail somewhere, but I can't find the darn thing. So I'll give the abridged version:
1. Get a little tinkly bell for the door she's used to going out of. Hang it from the doorknob, low enough that she can reach it easily with all four on the floor. Show it to her and demonstrate how it rings so it doesn't startle her.
2. When you're ready to take her out, hold the bell (so it doesn't ring) and smear just a little peanut butter or something else yummy and gooey on the tip of the bell. Let her lick it off, and open the door as
soon as the bell rings. The timing is pretty crucial, so as soon as you hear anything out of the bell, let her out.
3. Repeat every time you take her out. It should take about a week-and-a-half to get her doing it on her own, if you let her out 4 or 5 times a day. This is an agreement between you and your pooch; every time you hear that bell, you are obliged to let her out or she'll quit using it. Once she's learned it, you can insist on a little louder or more forceful ring before you let her out. But for now, be sure to listen for it.
4. It also never hurts to put the actual act of pottying on command. (Mine is "pee on that", which I know isn't terribly attractive, but it gets the job done!
) Pick a single command that applies the #1 and #2--a lot of people use "hurry up"--and say it while she's pottying. Then, when she finishes up, reward her. This command tends to take a little time to learn, but it's worth it when you have to take her out on a cold, snowy night! All my kids know that "pee on that" means you'd better do your business quick if you want it to get done!
She's still pretty young, so you can probably expect the occasional accident. But if you give her a signal (the bell) that she knows you'll listen to, you'll have a much cleaner carpet!