Negotiating a Relocation Package (Houston)

Hello guys. This is my first interaction here and I can feel I will find great advice and come across great people! :)
My husband and I are originally from Brazil, but have been living in Australia for more than 10 years now. We live in Perth and it looks like there's an opportunity for my husband to be relocated by his company to Houston. He works in Project Logistics. The company is flying him to Houston at the end of May for personal interviews and to close the deal (if both parts are happy). So I will say there's a 95% of happening, but nothing has been discussed in regards relocating package or salary, what makes me conclude the salary offered would at least match his current in Australia. This would be our first relocation and I would like your advice about what would be a good deal for us. We live a very comfortable life in Perth and want to make sure the move would not only be a good thing for his career, but also we won't struggle ($$ wise), specially at the beginning. It's just the 2 of us, no kids, no pets. We own a house in Perth, that would have to be leased, would need to sell 2 cars and decide whether to put the belongings into long term storage or ship it to America (my first choice). We do believe to be staying in Houston between 3 to 5 years, but it could be extended. So, what would be considered a good relocation package for Houston (even more, what would be a realistic relocation package within the resource related industry at the moment)? For the ones that have been there, what was offered, or should have been, what would have been important. Thanks in advance!!