3.3v power problem with mega 2560

I have a mega 2560 where i connect RTC1302/SD MODULE/ ETHERNET MODULE W5100 / LCD 240X128
when i try to run program i find sd card failed and ethernet work but if i disconnect the ethernet power the sd work !! And when i connect the power of ethernet and sd in external power 3.3v they work all
What is the solution please because some time they work all in the same mega power !

The w5100 and SD card are a bit power hungry. They can use up to 100ma each when operating. That is more than the 3.3v onboard regulator can handle.

From the data page for the Mega 2560:
DC Current for 3.3V Pin 50 mA