I want to buy Arduino Uno, but before I do that I want to know if its possible to control a motor and have a real time clock at the same time. This is important to me as I want to make a bell striking mechanism.
Before you buy a RTC or a motor shield, use the shieldlist.org web site to ensure that there is no conflict between the boards you intend on using. My recommendation would be using the Chronodot clock - very easy to use and program with existing libraries and very accurate also. It uses the I2C bus, which is relatively easy to implement (2 resistors, a couple of jumper wires) and the SCL/SCA pins (usually analog pins A4 and A5).
As for motor control shields, there are many to choose from. However, your problem re: motors may be even simpler depending on the strike / clapper your bell uses. A simple relay may be all you need.