You do not have to take the oral exam to take the HSK- they are separate. I sat the oral HSK (intermediate) in December, 2010. The exam is 21 minutes long ( 10 mins prep time)and it comprised of 3 sections. The first is imitating the spoken recording. The second is to prepare 2 minutes of speech using the pictures cues provided (2 of these questions.) And, the last section is 2 generalised questions requestions written in pinyin and characters for which you have to speak on for 2 minutes. For a sample exam go to: http://www.chinesetesting.cn/userfiles/file/HSK-zhongji.pdf

If you familiarise yourself with the format you will go well. You can easily get full marks in section 1 - by practising imitating radio, TV and lesson dialogues. I did not study for this and passed...but was certainly not happy with the result. Good luck!