Hi I'm new ad I have no experience on buying a property at online auction.  

I ended up putting about $19k of total upgrade.

If am the buyer and my name is Joe Patterson, I assume that goes on  line #1, .....but then what is #2 and #3 for?

They have asked me, and I have agreed, to be the broker for this new venture, but there are a lot of questions that I have and cant seem to find the answer for online.

Donald,Net worth is the same as any net: Assets - Debts.I am guessing that you want to know if the person your are financing has a pot to do their business in.Have them fill out a form 1003 (online for free) and pull a credit report.

BP is one of the best online real estate investment websites.

It has a huge backyard,and I can build another 900 sq ft 2 bedroom unit which I think will add $100k to the value of the property for a total of $300k.But there are no comparables, and my realtor could only give me duplexes which were only about $250k.My question is should I build this second unit rather than look for another "very hard to find now" flip?

I agree with @J Scott and @Manolo D. what anyone can tell you online or in a book is how that person goes about coming up with estimates.

Simple online mate. 

The trustee will usually be instructed to bid in on behalf of the lien holder the total of amount of the principal, interest owed, late fees and legal fees, as well as any other legitimate fees incurred by the lender.