Aristeer isn't perfect, but frankly, it gets the job done.. and in web development, that's 90% of the battle
Quick primer on the template styles.. basically, if you use the style of XHTML for the module inclusions, it will wrap all modules in a new div that has a class of "moduletable". If you set a module class suffix, like "-sidelike", it will then create the div with a class of "moduletable-sidelike", which you can then style individually per module. Of course, if your template has any other inherited styles on moduletable, that could cause other issues, but it allows you maximum flexibility for styling individual modules.
So... to change the class to XHTML, you'd want to edit your template's file that includes the module positions. Usually, this is simply /templates/YOUR_TEMPLATE/index.php, but could be else where. In there, you'll see the module inclusions like:
<jdoc:include type="modules" name="top" />
To change the style to XHTML, you want to update that line to:
<jdoc:include type="modules" name="top" style="xhtml" />
If there's already a style there, try just updating it. Since (for now), you only need it on the the left sidebar position, you might just want to only update that one jdoc:include line, instead of all, so that there's less of a possible impact.
Once done, you should be able to remove the CSS change I made above, and (hopefully) simply add the following:
.moduletable-sidelike {z-index: 10; overflow:visible}
Hope that all helps get you going, and maybe even taught you something. Should you need anything else though, you know where to find us!
Thanks,
Alex