PA services

I run a small business and looking for an assistant who can work both onsite and offsite. We are based in Central London and the work would entail: diary management, travel arrangements, booking entertainment, bookkeeping and the odd research job. Any Powerpoint and/marketing skills would be much welcomed. Initially the job will probably entail 2-3 working days (8 hours each), due to the back up, but anticipate this will fall off to 1-2 days once we're caught up.