What accessories do I have to add to my bike so that I may commute during rainy weather? I have a hybrid (Schwinn Sporterra) which I use for commuting except when it rains. The main problem of riding it during the rains is the dirt that gets spewn all over, esp over the drive-train. Cleaning it and re-oiling the whole thing is a painful hour long process. Due to this I tend to not take my bike out when there is a chance of rain. How do I get rid of this problem? 

I do have some plastic fenders, but they do not cover the wheels fully. If I get new metal fenders which cover most of the wheel will this problem be solved? Do I have to get any other accessories?
Adding mud-flaps to both fenders will greatly reduce spraying water on to your bottom bracket, feet and bicyclists riding behind you. 
Mud-flaps can be made easily &amp; cheaply by cutting a part of plastic bottles for milk /water/soda-pop and screwing them on to end of mud-guard/fenders (ensure there is enough clearance between screw and tire).
Plastic fenders offering full coverage will avoid spraying water and dirt; besides the plastic one's usually are  lighter and cheaper than their metal counter parts. These are also corrosion resistant.
Using wet weather chain lubricant will help to some extent, however this doesn't replace the need for cleaning your drive train and re-lubing it. This type of lubricant will help you to space out cleaning a little further. A clean drive train will last longer.