I am a programmer with 4 years experiences working with C++/C#, Unity Engine and Unreal
engine.
Seeing as you have a card game that is built using HTML 5, i take it that you will provide all the assets needs for the game? Also, a link to the game, or a down load link for the latest HTML5 built would be much welcome for me to gasp what function, along with input the game has.
Another question is that is it necessary for this game to be convert to Unity engine? Is there other option such as Unreal engine? I can work with either engine, but personally i would recommend Unreal engine.
I don't have much information based on this project description, but i think it will take around 10 days, more or less depend on the complex and the scale of the project.
I may need 10 days to complete this project, which can be divide into the following:
+) 3->4 days to implement the core function.
+) 3 days to set up the assets, material, deploy setting, etc etc
+) Any time left over will be dedicate to debug/feedback.
After complete the project and transfer all the required project files, I will also support feedback/ fix bugs for 2 weeks.