HTML Website Visual Enhancement

We require a visual makeover for our HTML website located at www.em.com.pg
The current file structure should be maintained with no changes of platform - we need to be able to continue minor editing ourselves using (very old) Adobe Dreamweaver 8 on our laptop (a major makeover with transition to CMS platform is scheduled for next year but for now we just want to tidy up the existing HTML + Javascript site).
Current project includes:
- tweaking all graphics and images to improve the look and the presentation of images
- tweaking the layout of text and image tables to improve download and appearance
- locating and fixing any broken links
- identifying and fixing any text or formatting not appearing correctly in browsers
- improving download and appearance on mobiles, tablets and a variety of desktop / laptop screen sizes
- improving SEO for better search ranking

This is a fairly straightforward web design task that is quite suitable for new freelancers with appropriate skill - we are not necessarily looking for a hotshot.
Using artificial intelligence or macro codes to perform repetitive or time consuming aspects of the job is permitted.
The task is not urgent but we would like it completed withing a month with staged partial uploads to our live site before final job completion.
Suggestions for improvement existing to layout and design are welcomed but will not be assessed as a performance criterion.