Galaxy S3 with Telus getting horrible reception.

Hi,

I used to have a very cheap (non-smart) phone with Fido (LG Gossip) and I could never really complain about the reception.

I recently switched to Telus and got the Samsung Galaxy S3 and have been getting really bad reception on my phone. My room is in the basement of our house and my old phone had full bars in it while my S3 gets only 1 and sometimes 2 bars and the line always cuts while I'm talking on it.

Same thing for a lot of subway stations. With my old phone with Fido, there were many stations (not while riding the train of course) where I had really good reception, but with my S3 I do not get that at all.

I went to see a Telus store today and they told me to switch my Network Mode from GSM/HSPA/LTE (Auto mode) to GSM/HSPA (Auto mode) and assured me that this will get me better reception eventhough my internet speed will be slower. However, I still get the horrible reception that I had with LTE mode.

Is there something wrong with my phone? Is there anything I can do to help or resolve this? Or is Telus' network coverage really that bad?

Thank you.