You will have to pay the whole bill then turn in the receipt to your insurance company when you return to your own country.
You'll have to pay the whole amount up front, then your insurance company will reimburse you after you submit your hospital receipt back home.
この場合、次のような言い方ができます。
ーYou will have to pay the whole bill then turn in the receipt to your insurance company when you return to your own country.
「診療費を全額払っていただき、帰国後に保険会社にレシートを提出してください」
ーYou'll have to pay the whole amount up front, then your insurance company will reimburse you after you submit your hospital receipt back home.
「先に全額払っていただき、帰国してレシートを提出後、保険会社が払い戻してくれるでしょう」
to reimburse「費用などを払い戻す」
ご参考まで！
カナダ 
