Hello Sir,
I am a magento , wordpress plugin developer .I have developed many plugins , some of them are very famous like multi-vendor marketplace for both magento and wordpress,Gift cards,ticket system etc ,but I work for a company thats why I cannot show them in my portfolio hope you can understand .I can surely do your work in the best way possible ,custom search bar no problem ,and I can create a new plugin for for sorting ads on your website or or can edit a the plugin you told.
If you want to hire me please come on chat so we can discuss it further.
Thanks