Now that you have used your AA miles, I would concentrate on quickly acquiring Continental miles before it merges into United. Both Continental and United are Star Alliance carriers. That alliance has lots of really nice flights to Europe. My preferences are Lufthansa and Swiss Air.

Take a look at what I have to say about Continental credit cards on my website below in the Credit Cards > Annual Fee Cards section. There are at least 65,000 miles (and maybe 125,000 miles) available for each of you from the Chase Sapphire and the American Express Preferred Rewards Gold cards. Then more will be available after you cancel your Continental card before the merger (so it won't automatically be converted to a United card by Chase) and then apply for a United card after the merger for whatever bonus they offer then.

Then take a look at my Finance section. There are very good brokerage offers for Continental and United (and others). Also, you could start to replace your AA miles via BankDirect.

From personal experience: It is essential that you get your girlfriend interested in and aggressive at acquiring her own free miles, so she can use them to fly with you. Years ago it took me a year to convince mine, and she has been behind me in total miles ever since.