Thanks for your post.
SQL Source control isn't really designed to be used to deploy a structure to different environments, it's purely to help a team of developers work together and record their changes directly through SSMS.
If you need to move the structure somewhere else, e.g. production to development, then we would recommend that you use SQL Compare.
In your situation:
1) Use SQL Compare to deploy the schema from your current production database to your development environment.
2) Link the development database to SVN using SQL Source control
3) Work on the development database until you're ready to deploy the changes to production
4) Use SQL Compare to deploy the version in SVN to production (or any other environment).
SQL Compare and SQL Source Control work very well together for this kind of process. There is a bit of information on how SQL Compare is integrated in SSMS for this task here
I hope this helps.