1. what are my responsibilities outside of my guild?
Eventually with any luck your guild will be ready for an alliance. Do talk to other guildleaders. Do ask other guildies which alliance they would like to belong to. Dont allienate your guild from having contact with any other guild.
2. I see that there are regular GM meetings, will i be required to attend? If so, what do they discuss?
Officer meetings? Yes! If you are GM you need to be there. United front and all that jazz. Same applies to guild groups IE: Ml's, Pl's, guild meetings, officer meetings, and do group some with your guildies. You cant be gm in name only, you will lose your guild.
3. I do not have enough gold currently to buy a guild house, will that be a problem?
Maybe not in the beginning but later down the road yes. I wouldnt try to start a guild until atleast your 40's. Before that you will have a hard time recruitting high end players that you will need.