I don't think so.
No, without extensive modifications you can only be connected through one network connection at a time. Find out which one has better throughput/stronger connection and shut the other one off.
Nah. But two router mods that I found to be helpful (if you can do them on the Netgear) were:
There was also a helpful suggestion of changing your WIFI card. Most laptops that is easy, but not all of them. Google for laptop's manual to see where it is located and what it will take to get it out. Definitely take in your existing card with you since they are not all the same. Sounded like you might be on a budget and not sure you are going to recieve that much performance gain for the dollars you would shell out.