I need help and advice with an account issue

If you still have the 360 this may help
support.xbox.com/.../switch-gamertag-to-different-microsoft-account

Think very carefully about putting your credit card details on there , I prefer to use pre-paid codes that are available at various retailers.Xbox live is well worth the money in my opinion so yeah , go for it.MS are currently giving away 2 games a month
free of charge(albeit some are pretty old,but free is free right).

My personal opinion and what I do is buy a 12 month gold subscription from Amazon, Walmart etc whoever is cheaper. As for xbox live accounts, if both of you want gold live then u both need to pay. As for games just as normal you buy a game either in a store
or on xbox live dashboard. The reason u need gold is to play multiplayer games, be able to use netflix, amazon, other apps but you still need to pay their subscription fee as well.

You can also try xbox gold free for 1 month when you make a silver account on your xbox, at least thats how it used to be.

Same happens to me when I'm playing MW3 and my brother is playing WoW.

If this happens to you -- the problem was that I had arrived in a vehicle and had simply left it in the road. The arriving convoy was crashing into my vehicle before reaching the fuel truck. Seems like a silly flaw in the game. Anyway, I moved my vehicle
out of the way, planted the C4, and went up the water tower. Game progressed normally.