Yes repair and adjust the present brakes... seriously you say your a novice, does that extend to your mechanical knowledge and or ability to use a spanner... Seriously its hard to know how much knowledge folks have form just a few posts...
That said if the brakes were un-balanced at the MOT then your first job would be to re bleed the brakes and see how that helps. 90% of the time the air in the brakes lines makes the brakes feel soft and ineffective.
From there i would check the servo (assume one is fitted) and the hose tot he inlet manifold for leaks
last item would be new pads in the callipers (assume discs are okay) the replace the rear shoes.
Where you find a parts that seized or leaking repair it... ask here bt be very specific about the part you are on about, use images and most important get a Haynes book...