Marketing Analysis and Suggested Plan to increase site users

We are looking for a thorough review of our current marketing efforts, an analysis of the market to attract more users to our site (its a free to use site that allows users to plan an event completely) and provide a marketing plan to increase the number of signups and active users to the site. The plan should be achievable based on a modest budget and should not simply be invest in SEO, PPC etc.

Note we won't share a budget, we would ideally like this asap - within 2 to 3 weeks after we award the work. We expect you to understand the UK market and have demonstrable examples of similar work. We don't expect you to implement the findings of the plan - this is simply an analysis of what we are currently doing, what if anything we need to change and a detailed plan of how to execute that.