Go to your install history in the your account section on the windows phone page. From there it should show up and you'll be able to reinstall it. Alternatively you can download the reinstaller app from the store and use that to reinstall it.
I too have uninstalled the app as it was not updating correctly, went to reinstall but cant find it anywhere.
I have attempted to follow the instructions above but cant see where I am meant to be looking. Any help would be much appreciated.
Thanks.