brakes squeeking and now the brake light on the dash is coming on

The light coming on just indicates a difference in hydrolic pressure between the front and rear brakes. If there is no leak at any of the wheels or lines, the master cylinder is the culprit. Sometimes they leak internally between the front and rear section. Sometimes it leaks out the rear of the piston. If you have power brakes, that fluid leaks into the booster and will eventually rot the diaphram inside. If it's manual brakes, it will leak right down the firewall and under the carpet making a big mess and eating all the paint off everything. Brake squeeks are usually more annoying than dangerous. If it's a scraping sound, that indicates something it metal to metal and needs repair. Squeeks are usually rusty hardware, loose brake pads, or a combination of the two.