this site has a good psu wattage calculator just click on what all you have and it will calculate how much wattage you will be using be sure to read what I have quoted below, it is the first thing on the site but I just wanted to make sure you read it ;) http://www.jscustompcs.com/power_supply/
Please Note: The Wattages listed below are maximum peak wattages for each component. The total amount this calculator figures is for all devices running at peak utilization. It is important to bear in mind that this amount will never be reached under typical operation. However we feel that this tool will give you a better idea of how much power your system will need. After all when it comes to power, having too large of a power supply is never a bad thing! It is important to note that power listings for some video cards are only estimates: the video card industry rarely reveal how much power their cards are drawing.
