Need help for configuration to make the 3D

I want to purchase a config to make the 3D! The company, where I work, wants to install a PC working on 3D (modeling, calculations, etc)

I have no budget but rather a specific price range! For that I am asked to find 3 config. pc that can meet their expectations!

- 1st config to make mini 3D (budget ~ Rs.65000)
- 2nd config higher (budget ~ Rs.97500)
- 3rd config level even higher (budget ~ Rs.130000)

In a second case, I would like advice:

- To make the 3D, the best is Windows XP 64 bit, Windows Vista 64 bit, or others?
- What graphics card needed?
- A Core 2 Duo or a powerful Core i7?
- What MOTHERBOARD?

I hope I am not too abused in my approach and I have answers as soon as possible!

Which modeling software you would be using?

Model only, or delivered too? (complex/realistic renderings or is it kind of modeling parts of a machine, etc?)

what I can already tell you:
- A os 64 bits certain. I have worked for 2 years under xp 64 and I'm past 6 months since vista 64. No significant difference was noted.

- The graphic card will depend on what you model, a graphic card input range can be quite sufficient.

- A quad if you are rendering. If that is the model you'll see a glaring difference between a c2d and quad unless the models are ultra heavy (although I'm not sure, it depends also on the program)

an i7 if you make big long well made. Brief, detailing the type of project.

Oops I forgot to specify the software! So currently, I work in Maya.

The company for which I am doing this research of product design, it would move towards a software Solidwork like to work from plans. Seeking realistic rendered 3D!

So to summarize: Proceedings of image and realistic animation.

OK, then take the heavy cpu level, an i7 920 if it comes in your budget

For graphic card, Maya not draw much benefit of a kind GTX260

For Solidwork, can be managed better, then I could not say.

6GB of ram would be nice too

if all this explodes the budget, a Q9550 is not lagging behind either, and you can stick to 4gb of ram