AEK Athens were kicked out of next season's Europa League for finanical irregularities on Thursday.
"It is a black page in the history of AEK," club president Andreas Dimitrelos said.
"We have a debt of 35 million euros and 23 million euros of this is owed to the state. We are asking help from AEK supporters. The next 15 days will be crucial for the future of the team."
Asteras Tripolis will replace AEK in European action in 2012/2013.
AEK were one of six Super League clubs dound guilty of financial irregularities.
The six - AEK, Aris, Panionios, PAS Giannina, Corfu and OFI Crete - retain their topflight status but cannot sign new players except for under 22-year-old Greek players.