hallo, I have a major problem with the internet service

since I started my contract with O2 I have this problem, it summarized into that: the WI-FI signal is very weak it does not cover all my flat (63 m2) although I placed the router in the centre of my flat and if I catch the signal on my laptop or my smart phone the internet connection is also not stable, I usually get the message of not internet connection or there is a connection problem even when I just browsing the websites. I called the customer service many times and they offered many temporary solutions like changing channels and installing o2 service suite with no hope. The main problem still present. I asked many friends here in Dresden whose have O2 DSL and they did not have this problem. They assured me that they can catch their WI-FI signal in the street. So please I need someone professional to solve my internet problem, I cannot wait for two years (duration of contract) suffering from this problem.

Note: I speak Deutsch little bit and English well.

Thank you

D.abdin