Generally, a water heater will last between 5-10 years, so yours is already past its prime. You should flush the sediment from the tank about every other month to keep it in tip top shape. This in itself should not cause your cold water pressure to be reduced, so you will need to remove any screens on your faucets and flush away any sediment there as well.
Some of the sediment in your tank could be from the anode rod, which is designed to be destroyed in order to save your water heater itself. The anode rod might need to be replaced as well, but my rule of thumb is when it is time to replace the rod, it is probably time to consider a full replacement tank.
Most hot water heater outlet pipes are just your common 3/4" pipe thread, which can be replaced easily. Just understand it may be similar to waxing a car as it is headed to the junk yard, so take a close look before wasting your hard earned money.
Finally, if you have any doubts or reservations on parts replacements on your water heater, please have a plumber come out to make sure the job is done correctly.
