I have the exact same problem with a Sony Vaio Pro 13. WiFi bandwidth is OK if I sit right next to the router but if I move out the bandwidth drops sharply. To quantify this I ran some download speed tests at different distances and my inexpensive Nexus 7 actually performs far better than the Vaio Pro 13 (see graph below). I labeled 35' as 'far' but it's actually really close by any standard.
I did contact Sony and their tech representative was not able to help. There is a thread on the the Sony Community and it has 538+ replies (as of this writing) since end of June so it's definitely a real issue for Sony. I bought this 1250$ laptop for my wife to connect to campus WiFi and now she's the only one in her class who can't get a connection.
