I think with the $ we have made through qualifying for the Europa league group stage, the NOVA deal and the Limnios sale we won't be selling Giannoulis on the cheap. Part of the problem is letting players enter the final year of their contract, they need to be renewed well before that. Giannoulis has 2 years left on his deal if we don't sell him this season (I hope we don't, he's extremely important especially given the 5-2-3 we've been playing) then we need to be working on that contract and sign him up.
Even if we intend to sell him next year it just puts us in a better bargaining position and we can get top dollar for him. Whether he wants to sign or not is another issue, I'm sure he has every intention of making the move to a better league. He may choose not to re-sign, so as to force the club's hand in selling him this year or next. We don't know that Limnios wasn't offered a renewal and choose to refuse it and hence he was sold.