how do i increase the range of a wireless camera ..note ..its wireless not wi-fi ..it runs on 2.4GHz..can i get a more powerful receiver ..?

If the system came with an receiving antenna you need to experiment with moving it around. I had to fiddle with my wireless 2.4Ghz security cameras and the antenna a bit to get them to work consistently. You also probably can buy an extension cable to allow the antenna to be closer to the cameras. It all comes down to doing all you can to get the receiving antenna as close to "line of sight" to all your cameras. If there is metal between the two it will not work well.

What is the distance between the camera and the receiver? What materials are between the camera and receiver?

Chance are high what you want to do is neither technically possible nor legal to do.

The transmitter power would have to be increased,

which would be illegal to do.

The easiest --- and maybe the only practical --- remedy

(whether you think so or not) is moving the receiver closer to the camera.

You do not increase the power of a receiver. You increase its sensitivity. You might do this with a better antenna, if it has one exposed. Antenna's MUST be the right length (¼ wave length, usually. ¾ will work too)

If the camera is hidden behind thick walls, floors this will affect the range. You may be able to get a directional high gain aerial for router (or camera), apart from that there is nothing you can to to make the signal more powerful, this is governed by wifi regulations that restricts the allowed output of wifi hotspots routers etc. to a predetermined level

It depends on a ton of variables here. NO not everything on 2.4 is WiFi. Cameras, cordless phones, baby room monitors, bluetooth, wireless keyboards, mice, and hundreds of other devices share 2.4 gig band!

The answer depends on what your camera uses and what may be available for it's use! A broadband 2.4 gig amplifier MAY be available or a 2.4 gig high gain antenna at the receiver end may be available to get more range from the camera. IF the receiver has an external antenna connection a directional 2.4 gig antenna is the easiest thing to add, it is also the least expensive resolution! Some cameras even have external antennas and can accept more powerful directional antennas aimed at the receiver!

Anything running on 2.4Ghz is wi-fi.