I am new to the PI. I am building a pi that will have cameras, sensors and all sorts connected to it. I am wondering even if I use an over powered power supply at 5.3v will it really be enough to run everything at full power? If not, then how do you provide more power to the entire system? Is there a regulated power supply for example?
You need to learn a little bit more circuit theory!! (This also applies to many more on this site).
You need a good regulated supply (PSU) that will supply the rated 5v ±5% at 1A. There is no merit is using a PSU "rated" at more than 1A. (This should be proper supply - not a phone "charger" - many of which have poor regulation).
Internally the Pi regulates this down to 3.3v for most of its internal circuitry (as mentioned by @ppumkin). Supplying a higher input voltage will just overheat this regulator.
The excess current (1A less that used by the Pi) is used for HDMI, USB and GPIO power pins. This is limited to about 300mA (1A less ~700mA) by the on-board polyfuse. If you need more for externals, you can use a powered hub (USB) and/or provide a separate source to the externals (which only need a common ground).
There should be plenty of power for running the on-board peripherals, including the camera, although you should avoid drawing extra current via GPIO pin 1.
You can of course use a PSU rated at a higher current, provided you bypass the polyfuse, either by supplying 5V to GPIO pin 2 (although there are many other access points), bypassing the polyfuse, or simply feeding in through the full size USB ports.