Replacing SAP

A certain amount of history is necessary to explain my predicament. The company I work for has had its share of ups and downs, and has just barely recovered from yet another low. In the last 3 years turnover has fallen from ?8M to ?2M and employees from 125 to 32. Around 1987 the company contracted a programmer to write an application to manage the business. As the company grew,the application grew, but the business was still relatively simple having only a handful of processes. When operators frequently made mistakes, the programmer was drafted in to make the system more foolproof.As the system became more foolproof, the calibre of the staff reduced. In 1998 the programmer decided to retire, leaving our application without support, and with Y2K looming it was decided to move away from our bespoke solution and prepare for the business to grow. A contract IT manager was hired to manage this transition and the decision made to implement SAP R/3. An implementation team of 6 was set up and R/3 implemented. Within 6 months the IT manager realised that the implementation did not match the businesses requirement and left, closely followed by the remaining 5 members of the implementation team who could now command higher salaries elsewhere. R/3 is now crippling the company both operationally and financially and needs to be replaced before December 2006 due to end of support. The difficulty I have, as IT Manager is that due to the need to stay in business, our business is now much more complex than it was in 1999, more processing errors are made and the business really needs a system that can pull everything together, be supported and adapted, with minimal external assistance. I've looked in detail at Navision and SAP Business One, but the cost of bespoking to cover just a handful of our processes is prohibitive (not to mention the problems this may cause for implementing upgrades). Has anyone had experience of a similar situation or words of wisdom to share?