Need help - I'm a REALLY new iPhone user in Bolivia.

[phone talk]

Hi there, I bought an iPhone from a guy here in Bolivia and I want it to run on my Tigo network. I have the sim card and everything.

Now, the phone used to work 100% - I could call and do pretty much EVERYTHING.

I decided to restore the iPhone using the Restore feature in iTunes. I did that and now the phone says the SIM card isn't 'valid'. I'm guessing I'm going to have to jailbreak it for my latinamerican SIM card to work, correct?

1. How can I check what firmware version I have installed if i can't even use my phone to open a single menu.

2. Once I know the firmware, what jailbreak version program do I need to use?

Are these even the correct questions to ask?

Thank you massively for all the help.