By now you have read most of the answers here which are all fine and dandy. The question or concern that I take from you is that you want to grow and need help with the everyday so that you can focus on your product, expand your volume and improve your market. As a small busniess owner I have seen many business fail due to to things: lack of discipline and lack of organization.
Discipline requires the fortitude to keep going even when things seem overwhelming such as you seeking out a Personal Assistant. Their are many computer programs available on iPad as well as other communication devises that can help in this area without relying on someone else. They pay for themselves in time and the only draw back is losing the device or not programming the data in correctly or failing to add an event on your calendar. Discipline with finances is key to maintaining assets and a budget. Spending money on an assistant will eventually drain your funds and place you into having to create a larger clientele base to pay for expenses. Remember that unexpected cost always arise without notice that you should have a fund for such an event.
This is where Organization comes in. Having your daily, weekly and monthly events laid out with ample time to adjust and be flexible for the unexpected will be the avenue for success. Flexibility and the understanding that you have certain goals that need to be met each day for this to go smoothly is also essential. Not everything will balance out, and you don’t want to stress the small stuff or you will be a slave to your endeavors instead of being free because of them. Set short term goals and confirm appointments, don’t overbook your day or week. Start small and eventually most all 80% of your schedule will come into focus smoothly.
All is hard work but I take it you are up to the task. I feel if you follow these two basic principles, you will not need a PA at this time. Good Luck and Have Fun.