Now I'm learning of Joomla now and i want to set up a site that with business goal, including news, forums and online shopping modules. Where can i find such themes?
it depends on the type of joomla version you want to user either 2.5 or 1.5, but i will recommend 1.5 because it will have all the necessary plug-in components and extensions that you required for smooth running of your website and the theme i recently discover was Cloudbase Template this template come with different colours and different module positions it is highly seo optimized with different choice of background colours and structures this temp[late is flexible and i have been using it for the past 2 years now and it working properly it is developed by a big company, this template is made to be use for news and entertainment sites for the demo you can check my site at www. timotew(dot)com and see the preview of this template, to download it search "cloud base joomla template" on google and follow the download link. there are also different joomla template on their website too you will see more incredible free and premium templates. in their site. this template can also run with virtual mart and joomla forum components with high seo optimization
I've listed some of the best providers in my Joomla Review, which I just wrote the other day. Check it out. You'll also learn more about how Joomla works and handles templating, etc.
You should search Google with keyword Joomla business template and you will have many results. You should get templates from popular Joomla template providers such as Joomlart, Rockettheme, JoomlaShine...They will support you whenever you need. I've built one website with JSN Epic template from JoomlaShine and it looks nice and professional. You can search and try the free edition.