You'll be fine. The SCJP for Java 7 is not going to make you any more or less valuable than having a piece of paper saying you are SCJP for Java 6. in fact the paper doesn't say much of anything, only that you're good at cramming information into your brain and retaining it for a short period of time.
More valuable is to actually do something using Java. Create a useful application, document it and be sure you can tell all there is to tell about the development history behind it, plus the design decisions behind the code. That really shows what programming muscles you have.
or when will be aviable SCJP for java 7?
Probably a few months after Java 7 is released, which is not soon.