what is the required power supply for this card
will this effect the supply to any other devices connected to the system
Theres no additional power requirements for this card, it runs off the 75 watts provided by the PCIe slot in your system. Your 450 w PSU is far more than enough. It will not have any effect on other components. This series of cards even recommended a 450w PSU for the whole system.
EDIT, just looked and it does take a mini molex connector (provides 75w additional max) which your PSU will have, still as I said it recommends a 450W PSU for it.