Could you please post a URL to your site (this can be done in the secure area tab if you prefer) so we can look for you. Without a link to page where the problem is on your site it is quite hard for us to provide the best solution due to so many variables. We try to provide file names and line numbers for code changes and if changes have already been made then our advice may be incorrect.
You should never code fixed dimensions in a responsive template.
Regards, Mark.
Please search forums before posting. Please make sure your post includes the version of the CMS you are using and a link to the problem. Annotations on screenshots can also be helpful to explain problems/goals. Please use the "secure" tab for confidential information.