Sigma 50-150mm F2.8 EX DC APO OS HSM

I have a d7000 and i have the nikkor 16 85 mm and the sigma 08 16mm in addition to the 35mm I'm missing a long range lens in my collection should i go for the sigma 70 200 or should i wait for this one to be released what i was thinking since there is a 300 USD between the sigma 70 200 and the 50 150mm i can use the difference to get a tele converter which will give me almost the same focal length as the 70 200 but with more options