If you process even just 1 profile within the 60-day time frame, the time frame resets - that is, you have a new 60-day time frame. Using this method, you can keep your GEDCOM on WikiTree.com for as long as you need it.
Are you having any specific problems processing your GEDCOM - tech problems (too many matches make your head spin) health problems (vision, dexterity), etc.?
If your GEDCOM involves only long-deceased individuals, you could send a copy of your GEDCOM to a fellow WikiTreer that you trust and who is willing to process the GEDCOM via his/her/their account.
If you currently don't have a trusted fellow WikiTreer available, I would be willing to process your GEDCOM, presuming you trust me () enough - just post back to let me know!