You're talking about your company's own internal IT department? Support hasn't been "outsourced has it"? And they won't come and put in a drive for you - and they will refuse to service the PC in future if you put it in yourself?
If the PC has just 1 gig drive it must be fairly old and would probably be incapable of recognising the new large hard drives on the market today. So if you wanted to put in a new drive without changing anything else it would have to be a used one anyway.
If I were in your position I'd stick the drive in (assuming you know how to do this) and if some other problem arose with the system that meant I needed to call the IT guys out I'd sneak the drive out again before they arrived
Here's a thought though - if your company is running some sort of mad internal market perhaps the IT department would be interested in buying a small used HD? Then they'd have one in stock to sell to you!
