My company charges out my services for $115 an hour - I'm a second year grad. Getting someone who can actually sign off on something - you're looking at upwards of $150 an hour. If you can find a contractor who has their own indemnity insurance you may get away with $100 an hour.
Assuming they're happy to sign off on the basis that the original control arm is sufficiently rated for the required duty and that the replacement will exceed it based upon the specs of the steel used and its construction - you'll be looking at least 5hrs min labor
