I would think it would be worth the cost to replace panes with proper glass as the corrugated stuff will always be vulnerable, has to be replaced frequently because the inside fills with algae, and is not cheap itself. You might well find old panes available from the freebie sites, or allotments etc.
Is there any way you can provide your greenhouse with a bit more protection from the wind? When it's cold and windy is just when you need your greenhouse most to protect plants, so you want it to be reliable in the wind.