Dear mate
I just check your site but seems it doesn't work so I can't access. I did migrate task many times, you can check my review if you want. I will update your Joomla 1.5 to Joomla 3.4.3 with Responsive template
What step I will do for you
+ Install new Joomla Fresh Latest version.
+ Move contents, articles, users, media,.. from old site [ database] to latest version
+ Clone new fresh template and make sure it is the same with old site[ if you want]
+ Create Responsive template for mobile/tablet device with new visual views. You can check directly in development time
+ Make sure all SEO Links work greatly as old site
Everything will be supported later if anything happen
All milestone payments only released all after you are satisfied about final results. You will have daily or hourly update about your project.
Regards
Linh