Which one to get Nikon d7000, Pentax K-5 or Sony SLT-A57?

Going to shoot macro, sport, pets (fast moving dogs), children, landscapes, wedding and night shoots.
I already did own Nikon entry level Dslr and its time to step up.

I like feature of bultin flash wireless capabilities and low ISO performance.

thank you for you answers in advance

Added (1). Do you mean that i can still shoot with my d3100?

It is Really a bad idea to jump from one camera system to another.

The D7000 performs very well in low light which is important when shooting sports and action.

There's NO reason why you can't be shooting sports and action now with your current camera

What you seem to need is not another camera, but some more lenses.

AF-S 60 mm f/2.8 macro
AF-S 70-300 mm for shooting sports and action
AF-S 10-24 mm for shooting landscapes.
AF-S 24-70 mm f/2.8 and AF-S 50 mm f/1.8 for weddings

You can forget the Sony SLT. It uses an electronic viewfinder and so the image lags from what is actually in front of your lens. For that reason it is not a good camera for shooting action of any kind

I hate to say it, but the Nikon makes sense in your situation.

You can do all that with your old D3100 but if you really want a better camera, the K5 may blow you away.

http://keerok-photography.blogspot.com/2012/09/any-dslr-can-be-made-to-shoot-anything.html

Yes, the d3100 will do fine for everything you want to use it for. The D7000 will do it all better, so if money is no object, go ahead and buy it. If money is an object, invest in a couple of good used lenses that don't overlap in focal range. The Sigma 17 - 50 f2.8 paired with a Tamrom 70-200 f.2.8 will be more than adequate for everything you want to do for about what you would pay for the D7000. Are these pro caliber lenses? Are they perfect? No, but they are both highly rated, and will do everything you need them to do.