Uninstall before Install

Can anyone tell me how I can run a bat file that will uninstall lync2010 before the lync2013 package runs?

I have Lync2013 all tested and ready to go, however it doesnt uninstall the previous version.

Basically all I want is to be able to run the below before the lync client starts the install.

taskkill /IM communicator.exe /F
MsiExec.exe /X{11849FBC-C416-4742-8279-17C3A2C85F72} /qn

Thanks in advance