IMO, if both of you have the chance get out of this country.

It is this country's law that forbidding you both from being together. Why a non-Muslim must convert after marriage. One simple reason, because the law says so. I dont think there's any obstruction between you two except for the law.

Dont you think it will be the best if you moved out from this country ? You can still practice Christianity and she stays as a Muslim. So what's the problem ? Its just like the case of a Buddhist marrying a Christian.