Ferroli Modena 102?

I have a ferroli Modena combi boiler since 2004 and the pressure keeps dropping to 0 initially it took several hours to do so but now it does it within 1.5 hours. We have to keep filling up the boiler which is annoying as its freezing and I have young children! Attempts have been made to fix the boiler with no luck. Also water drains from my radiators during the early hours of the morning but there is no water escaping from the overflow pipe outside apart from a little trickle every now and again. A pipe was added to the overflow pipe to try and establish if the water from the radiators was draining from there and it is not. So I have to fill the boiler as well as fill the radiators to make sure the house is warm. Desperate for a solution. HELP!