Code:
string spName = \"usp_Test_Procedure.sql\";
var tfsPp = new TeamProjectPicker(TeamProjectPickerMode.SingleProject, false);
tfsPp.ShowDialog();
_tfs = tfsPp
Install TFS Power Tools, on Source Control windows click with right button on Team Project or branch, on context menu choose Find > Find by Wildcard, just search files by names, not content.
If you want to search by content and name you can create a workspace and "get" that specific version locally. Then use the built in search in your OS or in Visual Studio to find what you are looking for.