It sounds like you have some air in the system. I'm going to assume that the brake fluid has never been flushed, as that is not a common maintenance procedure. BMW, for instance has this as something you do every 24 months to ensure the brake fluid has as little moisture in it as bad.
You're going to want to check on how much brake lining you have left. If the pads have more than 4/32" left, you should be fine. Most state inspections require a minimum of 2/32" of lining left, but it's generally not a good idea to let your brakes get that low. Assuming that your brake lining is good and you do not feel any vibrations, I'm leaning with the fluid flush. At minimum, while you get ready to do this process, you can check the condition of your brakes while the wheels are off.
You will need the following:
Brake Fluid (get whichever DOT specification your car calls for, typically DOT 3, but most German cars call for DOT 4)
A jack and jack stands
A set of metric and SAE (fractional i.e. 1/2", 3/8", etc.) wrenches
Some PB Blaster, Thrust, or other Penetrating oil other than WD 40
A friend to help you
A sharpie marker
Something for brake fluid to drain into
A plastic sheet, or nasty blanket to lay over your fender to protect it from any potential brake fluid spillage
First step, get your car jacked up and on jackstands (loosen the lug nuts and remove the wheels as you do this)
Next, once all the wheels are off of the car, locate the bleeder. On disc brakes - it will be towards the top of the caliper - it will be a nut with a nipple on it. On drum brakes, it will be on the backside of the drum. It will also appear as a nut with a nipple on it. Once you have located them, spray each one down with the penetrating oil. Do these before you do so much as take a wrench to any one of them. You'll want to give the penetrating oil a few minutes to cut through any rust that will almost certainly be present.
While you are waiting for the penetrating oil to do it's job, get the hood of your car open and make a line indicating the level where the brake fluid currently is with the sharpie. If the level is below the minimum level - skip this step.
Now top off the brake fluid resevoir. Do NOT start the car or run the engine while doing any of this procedure. Start with the right rear wheel and work your way to the left front wheel last. Have your helper get in the car and pump the brake pedal. Pump it three or four times all the way down and then hold it down. While it held down - loosen the bleeder, and let the fluid flow out - some bubbles should come out towards the end. Then tighten the bleeder, have your helper pump and hold again and loosen, let the fluid run and tighten it after the bubbles have gone. Then, have your friend try the brakes and see if it feels different. Repeat this process on all of the other wheels in this order Right Rear -> Left Rear -> Right Front -> Left Front. After each bleed, check the brake fluid level and top it off.
If you get any brake fluid on your hands - rinse them off immediately. As brake fluid is rather corrosive - it will eat through some plastics and the paint on your car, so handle with care.