I'll plan to buy UCM 7.0 Is it possible to install Unity/ContactCenter or other cisco telephony services on the server where UCM 7.0 was already installed or I should buy separate server for ContactCenter, Unity an so on?
You must be thinking of Cisco Unified Communications Manager Business Edition. CUCMBE is indeed a CallManager co-resident with Unity Connection, and can be installed on the MCS7828 servers.
You can find more information here:
Hope this helps.