I have two people wanting me to help them upgrade to 1.5.x I dont blame them. First of you need to install this file into your 1.0.x site
Go to components and read carefully. If you cant do this then pay me lll do it for you for $100 So you got your SQL file, right? Good. Let's continue:

I REALLY recommend you to make a new directory within the old install call it 'upgrade' look at the old sites config, what was your old sites prefix for table names? write it down on a post it note
I also recommend you making a brand new database and backing up your old database so you wont be a retard and lose all your sites content (right sCOTTo, ask him, he loves to delete entire websites 'accidently')
We want a 1.5 thats just been extracted and not installed yet
So we are at the place now on 1.5 that is starts to ask about username, pass, site title and DATABASE information.