Upgrading to joomla 2.5 doesn't cost much, but the real task is integrating virtuemart in the ecommerce site. But still your developer is asking for too much. Hence you can try searching for some other reliable and affordable joomla service provider who can do this task for you. <snip/>
Last edited by Mittineague; Jul 20, 2012 at 14:12.
There is no direct migration from Joomla 1.0 to Joomla 2.5.You must upgrade from 1.0 to 1.5 and then from 1.5 to 2.5. All the detailed instruction are published on Joomla documentation. You should have a look at these tutorials firstly and then consider you can do it yourself or hire some one.