I am trying to upload a localhost installation to a live host and have just found out that our hosting packing only has MySQL and not MS SQL...is it possible to use MySQL?

For all practical purposes it is not possible. I would recommend that you switch to a hosting service that provides MSSQL. There are plenty of them, and prices vary from free to various levels of "not free." There are some very good hosting services that cost $20/month or less. Some are much less.