I already posted the link for the db side of things.
This is for the sp side of things. First line of code should be.
SET TRANSACTION ISOLATION LEVEL SNAPSHOT
I must reiterate my warning that this will cause effect in your system. The load on tempdb will increase and I can't predict by how much. So you need to be carefull with this.
Made sure you understand the impacts of doing this because you'll be the one responsible for the system at that point, not me.