what management support software I need?

A specific application answer is inappropriate. Here is a selection approach -
Business Objective - you define. Example - 100% occupancy during the school year, or an annual rental revenue of x dollars.
Business Requirements - you define. Include all the things you have to accomplish (tax returns, insurance payments, mortgage payments, maintenance, payroll) and any applications you are currently using to do these.
Technical objective - support the business requirements. Turn those business requirements into a checklist, add a priority to each requirement (required, desired, optional) and then shop around for the application that meets your requirements best. Consider a service as an alternative to buying the software, since that may provide you backup of your data and technical support.