You can buy gold, but it violates the Terms of Service and shouldn't be done. That gold's usually from stolen accounts anyway.
To get your Mining caught up, you'll need to go back to Azeroth and run around the lower level zones a while. Sell all of the ores in the AH, and you'll start making extra gold, but the Artisan and Master flight training aren't necessary for anything, they're just nice to have. These routes should get you caught up quickly:
Enchanting works well with Tailoring, since it uses cloth drops for items rather than another gathered mat, so it's easier to make a lot of items to DE. If making gold is your priority now, drop Enchanting and pick up Skinning or Herbalism, get it caught up along with Mining, and sell that stuff too.
I'm not sure if there'll be a breadcrumb quest on the Hero's Call boards at 67, but you could go to Shattrath and find the Haggard War Veterans scattered around, they'll start a short quest chain to align with either Aldor or Scryers (neither matters much now, but you can check their quartermasters inside the banks to see if there's anything you want), and after that you can be sent out to Netherstorm. Or just keep running dungeons until you ding 68, and the Call boards should send you to Northrend.
Another option is to visit Zerid in Nagrand (http://www.wowhead.com/npc=18276), and do a few quests out there, one of which is Oshu'gun Relic
to replace that windmill trinket with something more useful. Watch for upgrades to the head gear and Agility ring too.
Oh, and if you can find some Brilliant Bloodstone
for the gear with sockets (or better yet, the Perfect cuts), it'll help them last a good long ways into Northrend.