BUYING FIRST INVESTMENT PROPERTY

Ok first of heres my situation…..my wife and I are about to inherit a decent amount of money ( will be able to buy our own family home outright, as well as have some left over)

due to other complicated reasons the money will be set up in a trust with a shell company as the trustee.

I’m looking at setting up a secondary company/trust for my property investing
I’m currently renting and it will be about 15 months until our home is able to be complete ( waiting for land the be released then build etc)

I was thinking of buying investment property through company name then renting it to myself until my home is built.

I figure why waste $25,000 on someone’s else mortgage when it could be on my own.

Now My question is I’m wanting a spreadsheet or program that I can input the numbers to know how it would be geared. I’m wanting the properties at this stage to at very least look after themselves. with no out lay.

One property I had in mind is listed at $529,000 though I think i could get it for 500 even. I would be able to put down the 20% deposit then plan to borrow the rest through the company with myself using my normal income as guarantee on the loan.

The only real renovations the property needs is Air conditioner installed. ( I know not a must but it is if I’m living there and its in QLD so almost a must)

Now looking at rents in the area I believe I could modestly get $480 a week a rent possibly more but for the sake of staying on the safe side i’ll assume $480.

I did punch the loan cost in to a simple app on my iPhone which put it at around 300 a month profit. but seems to simple of an equation to be right.

I know steve sells a program but I’m running a mac.

any help on how to crunch the numbers would be great.