Hey Wintermist
Now that the Uplay PC Client has launched you will always have the ability to redownload any game that you have activated with your account. Below are instructions on how to do that.
1) To find the download for the Uplay PC Client you will need to go to
http://uplay.com/
2) Once at the site you will see the orange download option in the upper right corner. It will say Download Uplay PC.
3) Once the Client is downloaded and installed it will ask you to log in with your Uplay account. Now that you are logged in to the account that you activated the game on you will see an option to redownload your game.