You can't outsource this work. Our database has grown to levels that are really pushing the database to it's limits. We tried to hire a small consulting team, and they wouldn't even do the work, just due to the scale. I have been doing the work myself but I am getting too tied up with other stuff, and would like to pass it on to someone that can really know what they are doing.
It's none of my business but.... Sounds like your current database is not cut for scaling up to big data, you should consider migrating from your database to another one that's built to scale. If i where you i'd consult a data architect not an admin that might optimize it a bit but is limited by the database's potential.
Just my 2 satoshis.