deployment and rostering system

We are a security guard agency and we deploy security officers across many locations, sectorised into North, West, East and Central clusters. In general, there are both day and night shifts for up to 12 hours. The total number (both day and night shifts) of the security officers deployed across at each location vary from 1 to up till 30. The composition of the team at each site is made up of permanent officers as well as relief officers. The former (permanent officers) obviously will be stationed at the particular site permanently and the latter(relief officers) can be deployed at only one sites or a cluster of sites. A software vendor had developed a rostering and deployment system but we are faced with multiple issues. For example, the system is very slow due to extensive MSSQL procedures consuming high amount of memory and we desire many changes that are not forthcoming. The system is using ASP.NET and we need expertise in this area to help us in resolving the issues as well as to lead us in this journey. We want this software to run faster and user interface need be improved. We have a vision for this software but these initial problems need be resolved before we can take bigger strides.