First, refer back to my comments to your thread in the Equipment forum: http://www.polevaultpower.com/forum/viewtopic.php?f=8&t=55939&p=222325#p222325
Second, make sure you read my post above (the one that Austin linked you to).
Here's a few more technical comments ...
You say you need a new pole because you're mushing this one, and you're landing at the back of the coach's box.
I agree that you will be needing a new pole once you fix a few technical flaws, but you're not there yet.
And I agree that you're landing well into the pit, but the only reason for that is because you're not finishing your vault. You're flagging out so much (and so early) that that's what's causing you to shoot into the pit. Once you extend more upwards, you won't be flagging out so much. This is by definition - no surprise here.
1. You're raising your pole a full 2 steps ahead of when you should be raising and planting it. Maybe that's something that a coach taught you early on (when your PR was < 10-0), but you're ready for a proper plant now, so plant it like a pro.
2. You have no trail leg at all. You need to work on that - a lot! I think my "It's Basic Physics" thread describes how to work on this, but if not, search for "kirk downswing" or "kirk highbar".
Once you fix these 2 flaws, *then* you might be needing a stiffer pole!