Hi,
I have all the right tools to do this work.
I am a web developer and I am across both ionic and native iOS development.
Some questions for you are:
1) how many screens are there in your app?
2) is your app already in the app store?
3) what is the complexity of your app? Does it have push notifications, integration with other libraries such as facebook, twitter or payment gateways?
4) what version of iOS do you target as a minimum?
This is a prelimiary bid; the final bid price will be more accurate if the above details are given.
Regards,
mmhleung