I would rather suggest you continue working on the startup. However, the idea of a co-founder is really great and useful especially if you are handicapped in any of the technological or other areas of expertise that is necessary for the growth of your startup. Do not rush to find a co-founder now, but you will get the right person at the right time provided you do all the necessary things with persistence.

To demonstrate, in my company we are four partners with two founding members and two other partners who joined the team in the third year and in the fifth year. All you need is a proper growth strategy in place and follow it. Let me know if I could help you in any way.