Should I Buy Domain Now?

It’s several months I have been passed on blogging. Lots of things I have learned, few of dollar I have earned by Google Adsense. All of the dollar I have earned by using my blogspot blog. Blogspot gives peoples a space where blogging is free. But they gives a sub-domainn like www.shamim-online.blogspot.com. Research and SEO gurus said that, if you want to start blogging professionally and earn smartly than it is mandatory to buy a .com domain. The SEO Specialists says that, .com domain gets higher importance from Google, Yahoo, Bing and other popular search engines. It is seen that, in the first page of all major search engines .com domain gets prevalence. It seems to me now that I should buy a domain now. Rather I will host my blog on blogger.com. However, I tried to buy a domain from Bangladesh but none of the reputed domain selling organization are finding now. There is a fear all time remains that, they may take extra money from me during the next year re-registration. I can buy a domain from GoDaddy by the help of Hasan Vai ( A Blogger of hasanonline.com). But there is a knotty thing while I am to be paid. What should I do now? I am in Tension.