1. Is the lappy going online somehow? If it is, you can use a LAN Cable and Internet Connection Sharing (unless you're one of those crazy people who use Macs, THAT'S RIGHT, I WENT THERE!). If that's the method you're doing, and yet you're getting connection issues, maybe your phone data provider has a cap on your bandwidth (in which case, there's not much you can do about that).
2. Does your carrier enable your phone to be a mobile hotspot? You can connect your PS3 to your phone directly, without need of a PC intermediary, if you give it the right type of connection.
3. Last resort: Mooch off of a neighbor's wifi. Maybe ask 'em nicely.
