I got bored and felt like modifying an existing Firefox search engine for CL to search Ottawa Erotic ads specifically. Code is underneath, you'll have to copy it and save as an xml file in your searchplugins directory. Works for me, that's about all the support you're going to get ;)
If you want to modify for your area, just substitute your city name for Ottawa wherever it shows up here. And if you're not using it already, try out Web Search Pro, an add-on for Firefox. Phenomenal tool for simple text highlighting and drag and drop searching wherever you want to look things up. Maybe if I get really bored, I'll do one up for CERB...
Copy code under here:
<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/" xmlns:os="http://a9.com/-/spec/opensearch/1.1/">
<os:ShortName>●●●●●●●●●●</os:ShortName>
<os:Description></os:Description>
<os:InputEncoding>UTF-8</os:InputEncoding>
<os:Image width="16" height="16">data:image/x-icon;base64,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</os:Image>
<UpdateInterval>7</UpdateInterval>
<UpdateUrl></UpdateUrl>
<IconUpdateUrl></IconUpdateUrl>
<SearchForm>http://ottawa.●●●●●●●●●●.org/ers</SearchForm>
<os:Url type="text/html" method="GET" template="http://ottawa.●●●●●●●●●●.org/search/ers?query={searchTerms}">
</os:Url>
</SearchPlugin>