I believe there is no limit as long as you can afford the filing fee. Habang tumataas kasi ang amount na kini-claim mo, tumataas din ang filing fee. Also, you cannot be 100% sure that the court will grant it. at kung hindi maibigay ng mistress yung amount? Hmmm.. wala lang. wala kang mgagawa kung wala siyang pera.
About sa support; You can ask for both of you and your child, pero humingi lamang ng maayon sa actual needs nyo. Being the mother, you also have the obligation to provide for your kid. Isipin mo din na kailangan din ng provider ng pera sa mabuhay.
If the recording was obtained illegally, no.