Hey Prasad.
I picked up a $5 chinese made 1' long box wrench at a local discount place. If you have a wal*mart around (and who doesn't?), I'm sure you can find one there as well. Box wrench = pipe wrench...same deal...same great tool.
I'm still thinking it's a loose sway bar link...I could be wrong, but I had the clunk-over-bumps for about two days after SLIGHTLY loosening one of the sway bar links prior to doing my sachs install.
I was SURE that I'd gone through a thrust arm bushing or something...but I got under the car and just started shaking things until I found the loose component...then felt really really stupid for forgetting to tighten it up the last time I was messing with it.
again, if you're getting a clunk, you should be able to reproduce it by putting the car up on jack stands and checking for play in the various components.
Good luck mate.
best, whit