The Cost of Confusing Print & Web Design

I've been trying hard today to explain to a client in non-techy terms why it is less than ideal to have someone who mainly does print design work on the look & feel for their website update.

Now don't get me wrong here, I think the designer does good work in the print medium and actually I quite like their aesthetic but, when asked by my client how we might go about cutting costs for the site update, I mentioned that in our previous dealings, their graphic designer
1. Was not providing me with PSD files with each graphic element occupying its own well labeled layer for easy slicing and dicing so I was forced to spend time basically digging out graphical elements I needed to implement the design in XHTML.
2. Was causing extra (and otherwise unnecessary) work for me because they had not taken either standard screen size or the size of interface elements such as form controls into account when producing previous designs.
3. Had obviously no eye for adding elements of design that could be rendered via CSS rather than by using graphics thus making the design much less flexible and reusable not to mention a heavier download.
4, Had produced designs in the past with features that were awkward and time consuming to implement in XHTML
and that all these factors were contributing to cost - though, to be fair, probably not as much as the constant revisions of the copy the client made themselves during the last site build.

There are also indirect cost implications in deploying a site that carries usability issues

These are difficult points to communicate to those outside the web design and development fields and I remain unconvinced that I got them across.