Landlord seeks property management software

We are landlords of an apartment building with six tenants, plus four private apartments and one commercial apartment. We are looking for property management software to assist with administrative tasks.

The software should meet the following requirements:

• The billing year for the building ends in October.
• Heating cost billing
• Importing transactions from the banking program (Star Money)
• Graphical consumption analysis would be desirable
• Network capable
• If possible, no obligation to purchase an update every year.

Two workstations are planned.