Create opencart popup checkout window using ajax for opencart

i need an costum popup checkout window so this popup content only load when we click view cart. this popup will using vqmod so no file replaced, when user not logged in the order will be create by specific customer id i give, but when user logged in it will using user customer id. below ingin dropship theres 3 column need to fill. but if in past time user already checkout with their id and using ingin dropship function then the data will be appear automaticly everytime user reselect region or city or editing product qty or remove product it will refreshing the shipping method cost/weight after user checkout it will not directing no any other page, inside the popup will showing Success you have made an order Your Order ID: ..... Please Transfer the money into below bank account .... .... after user close the popup and reopen. it will shows Your cart is empy and there's no this form anymore till there's any product added to cart. also need to make new table in my database to showing city and region data so in this database there's region id so when user selecting a region it will showing which city is match with that region id