3 case fans, 2 three pin connectors...

[damocles]

Best the solution to run one of the PSU?, can I get an adapter?

 

[Mitzi]

Yup, get a 3 pin to 4 pin molex adaptor, cost peanuts.

You wont be able to monitor the RPMs of the fan connected to the PSU though (I think there is a way around it but I don't know what it is).