nginx,hhvm,mysql speed/no downtime fix in digital ocean

Budget:30$,Please bid only if you have minimum of 5+ years experience in running high end [login to view URL] apply if you can start now. 1)Server is running with 8GB of RAM,UBUNTU 16.x 2)Nginx,hhvm,php,wordpress. 3)Api calls are more than 100 hits per 10 seconds. 4)Server becomes slow at peak times and slows down very much ,need to have great speed and no downtime at [login to view URL] add load balancer if this can fix the issue. 5)This is 1-2 hr job for expertise.