New Camera or New lens?

I have a question, that I posed in another thread, but somewhat different. Here goes. What would be the better option for indoor Low light photography without use of a flash? Here's the thing.

Sony A550 with a top of the line say Zeiss 35 f1.4 or 85mm F1.4 Planar T

or get a better camera ie A99 and use a middle quality lens? If a picture taken from each camera at say F2.8, indoors, no flash, high ISO setting, would the Better Low noise A99 with mediocre lens produce a better image or would the A550 with the Really good quality Zeiss lens produce a better image.? I'm guessing the A550 with Zeiss. Main reason for asking is I don't want to make a purchase and regret making it due to lack of research. So save for the Zeiss or keep my current lens line up and buy the A99. Also, is the Low noise at high ISO capabilities both due to camera sensor and Quality glass, or does one over ride the other in terms of IQ at High ISO. I know it's a lot of info, and I do hope I was clear enough. Thanks in advance...I'm fairly certain most would say always buy Good glass, but I just wanted your take on the subject.

As a side note, I do own the LAEA-2 adapter, so I could use the Zeiss on the NEX 7, if that makes it even better

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Sony NEX 7, Sony A550