HOW TO RECOVER SOFT DELETED EMAILS ?

The exchange email inbox, which is available for me alows a max of 920 MB message storage space. When the mailbox reaches 720 MB, an automatic pop up message starts receiving saying "your email inbox is almost full! Please reduce your mailbox size. Delete any items you don't need from your mailbox and empty your Deleted Items folder." But, what we actually do is we move the excess messages to a different folder, as a back up to hard disk (in the form of .pst).
While doing that exercise, a total section of email inbox received from "06th March 2014" to "15th March 2014" was deleted accidently by me. The reason is when you select them all (using "SHIFT" key) and "RIGHT CLICK", you will notice that, the "MOVE TO FOLDER" and "DELETE" options are very close to each other, and that made me victim of this accidental email deletion.

I will be very thankful, if you can give me an idea, how to recover those emails. If those are recovered, it will be a great deal for me.

The OS is Windows XP 32 Bit Professional, and MS Office Outlook 2007.

Thanks in advance.
Dattatraya.