WCF Data service query

Hello,

I am using WCF data service to get data from sql database. I have written one query which takes longer time to execute. i want to improve this expression to get only the columns i need. I could get column from Table1 but not able to find column from Table2 in example below. Appreciate if anyone could help me with this.

var list = DataContext.Table1.Expand("Table2").Where(T => T.Name = "Test").ToList();

on the similar lines i have one expression which goes like:

var list = DataContext.Table1.Expand("Table2/Table3").Where(T => T.Name = "Test").ToList();

how to get specific columns from 3 tables. alternatively please suggest how can i reduce the response time.