Tough choices here when you feel like the clock is ticking. I can tell you that I've heard moms have *wildly* varying experiences here. On average your period comes back around 14 months if you breastfeed on demand, but it can range from 4-24 months. I exclusively breastfed my son when he was young, and continue to feed him 2x/day now that he's 16 months old. I started taking Vitex (an herb) about 2 months ago to see if I could coax my cycles back again since we are interested in conceiving a second child. I finally ovulated 4 days ago, for the first time (!) I think it probably would have happened on its own by Christmas of this year, regardless of the Vitex.
If you continue to breastfeed your baby you will probably start menstruating arond the time she's 12 months +/-, or when you wean her. Other things that can jump start it include abruptly cutting back on nursing (you may not have to completely wean). Lots of people I know had their period come back when they were down to 2 feedings or less per day. You just need to decide whether you can stand to wait another few months to conceive. I will tell you that I think having kids really close can be very tough for the first year. Good luck whatever you decide.