There is a way to make an X10 camera repeater. Basically, you need a wireless video sender and receiver.
You set the receiver on the channel of your camera. (say, camera=A, repeater receiver=A)
Connect the receiver video output to the sender video input with an RCA cable.
Set the sender on a different channel. (say, C)
Set your ultimate video receiver at the computer to receive the second channel. (C in this example)
By careful placement of the 'repeater' setup, you can boost your range.
I do want to add that once I turned off my WIFI, I had great reception, except when the microwave oven was on, and one time when my receiver fell down and was facing the floor... I have since wired the cameras for recording, but use the wireless to see who's there on the TV. I should also add that the 2.4GHz reception was poor near my computer monitor or TV. A longer RCA cord and separating the receiver may be all that is necessary.
Good Luck!