I'm also having this problem, and I tried deleting the cookies as sgunhouse up there suggested, and it didn't work. Being stuck on the crummy old version of Google is starting to drive me crazy, and I like Opera too much to switch to another browser (ESPECIALLY not Google Chrome, if this is a deliberate attempt to get me to start using it. I won't be coerced!)
What else should I do? Is there an extension I can download to force new Google, or should I try getting Opera Next and see if Opera's patched in a fix for it?