Making a site Mobile friendly

[frank]

You said it yourself that your site is complex so I think that you should buy the theme from the owner.

So in the future if there any problem rises you don't have to worry about it the owner will take care of it.

Don't think about now think about the future. Yeah, surely you can make some changes and make it responsive (with the help of online coding lessons). But can you be sure that there will be no problems in the future.