Does Spherion Staffing give raises? I am working for their client who is a high profile beverage company but..?

but since I started in April I have basically assumed alot of respobsibility (Supervisor/Lead) Level. I even sign and initial in paperwork where it says Production Lead Transactions. I was hired as a "data collector" the person who was doing what I do is a lead getting paid 11.00 more than me. The manager told me that since I was doing a better job and am grasping SAP more than the lead was that she was giving me all of the responsibility ...ontop of what they hired me to do which is data entry. I also now assist finance with resolving accounting discrepancies in process orders. So i think its only fair that my pay reflect all of my responsibilities.........anyone work AT spherion who would know if I could get a pay raise (not a little one either) or anyone a hiring manager/hr expert at a staffing place??