You can get list of your senators from senate.gov, not sure which one will be pro-immi.
Never the less, senators can not do much except inquire about a case. They do not have power to make case go faster or override a decision by USCIS. They have a person who forwards your question to USCIS and sends back their reply to you. Only advantage is, USCIS usually replies to the quesion from senator's office.