This is not a big deal I make your template responsive and mobile friendly, work around the existing css without problems! If you want I can convert your existing css to sass (scss) so you will be able to make modifications faster and easier in the future! I bill you max 20 hours for this project if it's not done within the 20 hours I will work till it is done for FREE.
Of Course during the project and after I will be online on Skype that you can talk directly to me and contact me for any problems in the future.
I'm really easy to work with and hope to can work with you on this project!