Our Avocado Seed Sprouted; Now What?

Every time we make something with avocados in it: guacamole, omelettes, tuna salad...the pits somehow find their way into a glass of water in our kitchen. 

My husband's been trying to grow an avocado tree from the pits for what seems like forever! With the help of a few toothpicks suspending the pit in water, we've had a bit of luck with the seeds eventually splitting in half and starting to grow roots.  The one that looked the healthiest met an unfortunate thing when my husband accidentally dropped the glass it was in off the balcony (what is about him and that balcony?!)

So we started back at square one with a brand new pit and out of nowhere this one surprised us! I was cleaning the kitchen one day and I noticed this thing had shot straight up in the air.  Within a few days it had leaves! This is what it looks like now.

So now what?! Has anyone else had success growing an avocado tree from a grocery store avocado pit? What do we do now? Can we grow it in a pot on our patio here in Idaho or is it a lost cause?

If you have any advice, let me know! We'd love to keep this little one growing if we can!