banner design

We are an event company with a conference in April. We need to create a variety of banners for various websites and electronic newsletters over the next few months. We are looking for a designer who can respond rapidly to our requests. The work is likely to be one or two items a week for a month or so but as we get closer to April there will be more things to produce -- signage, postcards, adverts etc. We would like to pay by the hour for each item