That is actually a fantastic problem to have.

We went through a similar situation during the early days of my startup.

You really have two options: either recruit sales people or automate the process by improving your conversion funnel.

If your deal size is as large as you've mentioned, ($20K), it might be in your best interest to hire a real person/team to do the closing.

Recruiting, vetting, and working with a killer sales team, is completely different discussion.

Hope that helps! Happy to answer any other questions you may have :)