When should you seek advice? You should always seek advice before the property settlement agreement. A qualified financial adviser will be able to assess whether you are making the right decisions in respect to the best split of assets for your particular needs and will give you an idea of what you can expect in the future if you proceed.
The best place to start is putting together all relevant documents and information that may be required. Locating and collating items such as all bank statements (including credit cards), loan statements, all insurance documents, superannuation information, any investment figures (rental properties, share information), and if applicable Family Trust details. Most recent tax returns and payslips are good to have to hand also.
Collation of these items will help you and your financial adviser understand more fully where you are situated and will allow him/her to put together a plan that will maximise benefits and minimise tax payable.