Hi Fuschia. Welcome to the Board! :D
With just a quick search, I found three patterns that may get you started.
http://www.laurassewingstudio.com/Se...alker_bag.html
http://www.bevscountrycottage.com/walker-annes.html
http://asgrichmond.netfirms.com/char...er%20caddy.htm
There seem to be quite a few out there, so if you don't like any of these, Google any of the following type search terms: senior patterns, mobility aid patterns, walker pouch pattern, walker caddy pattern, walker bag pattern, etc. You should be able to find a whole lot more.