Balance shaft timing and noise?

With the motor at top dead center the balance shaft assembly should line up like this, doing the same job right now

Please I need to know where I can get a cheap block or even just the balance shaft, one of the wood looking gears of the balance shaft on my 2003 Camry scattered into pieces, found most of it in oil pan when I dropped it and the remainder was sitting there in the balance shaft when I eventually brought it down. The crankshaft looks healthy, so I'm thinking just changing the balance shaft and rebuilding the timing kit will suffice. Please advice and most importantly, I need to know where to buy the block or balance shaft. Thanks

Driving the camry, started to hear a clicking noise, sounded internal engine but was not sure. This went on for about two weeks, as this is my daughters car. Then driving the car on interstate, noise got louder, cruise control caused trans to up shift, higher rpms, then boom. Got it towed, only tried to start once before tow truck arrived, noticed no oil pressure. Finally got around to removing the oil pan, found balance shaft gears broken and bearing spun, damaging the upper oil pan. So, now I have a used upper oil pan assembly with the balance shafts, from a salvage yard. I have heard of some type of timing that needs to be done and other things, I was looking for procedures, and difficulty. I am a mechanic, but with diesel engines, never seen balance shafts before. Should this be a job I should tackle, or get professional help. I can follow instructions, just not real confident on this job. I removed the bad balance shafts but not the upper oil pan, and I know the upper oil pan will have to be replaced because the balance shaft bearings caused damage to casting. Thanks for your help. Martin

But there is nothing wrong with the top end, crank looks good, just the balance shafts failed, why can't I just replaced the upper oil pan and the balance shafts?

I have looked on youtube and searched the web for info on this engine, there are some that look like its the right one, but not really sure, any links, this is a 2az fe motor, 2.4 liter. Also, is this a repair that I probably can handle, like I said, I am a mechanic but on diesel, never seen so many timing marks much less a balance shaft assembly, ever done this kinda job before? I just don't want to do something wrong to cause the engine damage and ruin the car. Sorry for being a little OCD, just want to be careful before I begin to pull things off.

Thanks for the advice.

Perfect, thank you very much exactly what is was looking for. And thank you for the quick response.