Looking for a PA to help me free up some time

I've been playing with the idea of hiring a PA to help with organising and basically managing my day-to-day work life.

I run a design agency here in the UK and we're just a small team of 8. I'm working a lot on client projects, scripting, filming and editing youtube videos, podcasting, and freelancing.

I'm getting to the stage where I'm working 12+ hours per day and don't really have any time to work on other things and things like the company accounts are getting neglected.

I've never worked with a personal assistant before so I'm really wondering if you could help me figure out the benefits of having a PA and what kind of work could you help me out with to burden my load?

Thanks!
Declan