Upgrade & Fear

Hi. I'm looking for some guidance on how I can upgrade and not break my site and put my client out of business. Here's where I am: I am using ata 3.5.3 on WP 3.1.

To allow different sidebars on various pages, I used the Shiba Widgets plugin and the plugin isn't working anymore. When I try to manage the widgets, I get this error: "Fatal error: Call to undefined function tag_rows() in /home/content/a/b/e/abekurek/html/wp-content/plugins/shiba-widgets/shiba-edit-widgets.php on line 212". Of course I've contacted the plugin author but got no help.

I know I can just apply the ATA and WP upgrades and do my best to rebuild the site but here's my issue: because I can't see the widget content in the admin panel, I will have to build all the sidebars from scratch. And that will put my client out of business while I'm scrambling to rebuild.

Can any of you smart people recommend a path for me to recover the 'hidden' widget content for my client and bring his site up to speed? Here's the URL: http://abetheinspector.com

Thank you!