Kiseimaru
well there are many ways to connect sentences... though I would have to say that the most common would have to be using the "te" form.
As for your sentence, it would be:
私は日本語を三年ごろ勉強しています。
While Narau is "to learn" what you've been doing is "studying" so benkyousuru would be better. Using "teiru" means that the action is still on going and the goro is the "about/ roughly" ... I'm not sure if your "goto" was a typo or not ^^;
thanks it helpd me..i understood watashi wa nihongo o san nen goro- and thoes 2 kanji after got me..i only know lik 130 and i dont kno thoes 2..wat verb are they? do dey mean benkyoo shiteimasu?