There are several possible causes, and each calls for a different contractor type -
1) if due to surface water seeping along foundation and coming up at the house-patio interface, then you need a Landscaper or Earthwork contractor (if a lot of work) to regrade your yard near the patio to drain away from the patio area
2) if due to roof leak where summer room meets house, seeping down between the two and popping out at the foundation, then a Roofer
3) if due to a leaking pipe, a Plumber - shut off all water flow in the house and furnace, then put your ear to a faucet or pipe and listen for water flow. To hear what it sounds like (because you may hear the gas flow into hot water heater or furnace pilot), turn a faucet on just a tad and you will hear the water flow - just a tiny trickle can be heard.
4) if due to chronic high water table that cannot be reasonably remediated by surface drainage around the house, then a Basement Waterrpoofing contractor is probably what you need - he will have to drill holes along the interface joint and inject waterproofing sealant gel or grout to shut off the water inflow.
5) if due to gutters dumping water near the patio that then seeps along the foundation joint, then a Gutter contractor to install or move downspouts, or extend them away from the affected area.
For the mold treatment get a mold remediation contractor, or read the how-to's in the Home > Basement Waterproofing and Home > Mold categories of questions and answers in Browse Projects at lower left.