You could go to
www.usairways.com and look this up under the "Dividend Miles" tab.
Here's what I found...
You may be given an opportunity to apply for a CC and make a qualifying purchase, but its for a limited time-frame. Outside that, you'll have to pay a fee, and I quote:
"With our new Mileage Reactivation Policy, Dividend Miles members have an opportunity to reinstate forfeited miles for an additional 18 months for a fee:
$50..... 1 – 4,999 miles
$100... 5,000 - 19,999 miles
$200... 20,000 - 49,999 miles
$300... 50,000 - 99,999 miles
$400... 100,000 or more miles
When you pay to reinstate forfeited miles, you must reinstate the entire balance of forfeited miles. If you do not reinstate forfeited miles within 36 months of the last activity date at the time of forfeiture, forfeited miles will be permanently deleted from your account and may not be reinstated."