Usb stick with sim not having signal

Dear Sir/Madam,
 I made an internet contract last week with O2 and until the activation of the normal line, your colleague provided me with a sim card with 5GB and a USB, as seen in the previous mail you sent me.The problem is that O2 has a very poor signal at my house (Am Marktplatz 10, 82152 Planegg) and I had mentioned that to the sales person. As a result the internet has a very poor signal only at the kitchen window and is completely useless everywhere else in the house. Is there any possibility we can do something to overcome this difficulty? Yours sincerely,
Alkmini Papadopoulou