Forum Moderators: not2easy
Welcome to WebmasterWorld :)
You have photoshop/fireworks/GIMP..?
Open you logo file in one of these - edit your (white) canvas to a size that suits, and place the image where you feel you want it - adjust the transparency of the layer that contains your logo (about 15%) and save for web/export... If you want B/W version convert the logo to greyscale first.