creating advance custom property for a web part in sharepoint 2010

so far i able to create a custom property with with single control something like this:

string _property1; 
public string Property2 
{ 
     get 
     { 
         return _property2; 
     } 
     set 
     { 
         _property2 = value; 
     } 
} 

but i am looking to have little bit advance something like this:

a textbox with dropdownlist

any idea how would i do that or any link?

Thanks