Check some of the end of season sales. For kids your size, there are tons of cheap options available. A good site to check out might be the EVO Store, they are a pretty sick company, and they have some good options. You're going to want something about 155 cm, or longer if you expect to grow this summer and want something to ride next season as well.
Since you are going to be growing soon, and growing a lot for that matter, you should spend less on skis, and more on bindings. When you outgrow the skis, you can take your bindings off and put them on a newer/larger pair. If you have only mounted your skis once, you can sell them used to make some money back.
For bindings, I would look into some Rossignol FKS 140s
Or Look Pivot 14s
Both of these bindings should work for your weight and ability level, although I'm not sure if you're shoe size is big enough quite yet. They also have a DIN range that will allow room for growth, and probably be useful into your late teens. These bindings will also be safer for your knees as you are progressing on jumps and rails, which is really important, especially while you are still growing.
You can probably find either of these bindings used for cheaper, and this would help keep you in the 450 dollar price range for Skis+Bindings.
When I was 12, I was skiing on non-parabolic Rossignols, and I wasn't even considering hitting jumps. With you're early start, I expect you to be spinning your age in no time, so, post Vids of your first Dub 12 soon.