Hi,
I am sorry,as per your job details you need a Custom eCommerce website on Yii framework that's not possible in 2-3 weeks of time-frame ,But if you need on immediate basis you can go for wordpress/opencart .
Indeed, I am new on freelancer portal, but having 4+ years of experience in Web design & development and working on other outsourcing portals via latest technologies alike(Responsive design ,CMS, eCommerce ,shopping carts , PHP, Code Igniter, HTML5, CSS3) and have good reputation on them. For an enquiry you can search on Google by Trios InfoTech.
Looking forward to work with you,
Regards,
Arun