Hi Alan and welcome to the forum. With regard to the annulment process you have just made mistake number one, speaking directly to the attorney and in doing so letting him know that a foriegner is involved. This is likely to vastly increase the price, so it would be better if your gf shops around, finds other attorneys and compares prices.
There is also an alternative to annulment if your gf's situation fits (or can appear to fit) the criteria and that is called "Presumptive Death for the Purposes of Remarriage". This is something you might want to look into before going ahead with annulment because it is usually both quicker and cheaper.
Whatever she does, she should find an attorney who will give her an absolute (package) price with payments being made at each stage of the process and with a large proportion of the money only being paid on absolute completion of the process.
Filipino attorneys are notoriously greedy and if she doesn't do this it's likely that the price will increase as the process goes on and that there will be additional court hearings needed (which she of course will not be required to attend) each one costing between P5000 and P20000.
With regard to your question, getting a tourist visa isn't that easy and especially if the lady in question is still married to someone else, but it always helps if she has the three things that the ECO's look for when deciding on a tourist visa which are, a good job (preferably government) in the Philippines, property in the Philippines and money in the bank in the Philippines.
Without any of these the ECO (Entry Clearance Officer), however unfairly, will probably conclude that if she was given a visa, she would be unlikely to return to the Philippines when her visa expires.
Iain.