How do I get the TYPE that a given string represents ?

I have a database with all the Entitiy's entities stored as a string. So I basically query the database and return a list with the entity names.
And I need to get those string, convert to the appropriate type, and pass to a Method called GetTables that receives a parameter of type TYPE .
public override Object GetTables(Type tp) Can anybody help me converting those strings to the entity in order to pass as a Type to the GetTables method ? Thanks!