How to recover coins from a wallet that uses BIP32 Deterministic Keys?
Here's a web tool for BIP32 key derivation.

The only problem is the hardcoded 50k rounds of HMAC-SHA256. You do need to know how your wallet software exactly derived the master private key from the mnemonic or you'll get totally different keys. Unfortunately there's no standard convention for the HD wallet backup/restore process and I'm afraid this ranks quite high among the biggest downsides against Bitcoin adoption.