Okay, I'm not a guy, but I'll volunteer an opinion.
Is the money problem recent? (Like, ex just recently stopped paying child support?). If so, wouldn't it make sense for her to mention what was going on in her life?
Have you mentioned to her any ideas for how she might budget her money better? (You know, the old "teach a man to fish" concept?). If so, how does she respond?
Although I'd definitely be leery about taking on her financial problems for her at this early stage of dating, if she's this strapped, it would be a nice gesture to pay for the babysitters when she goes out on a date with you.
Consider, too, this side of your response - it doesn't seem to me like you would be too eager to take on financial responsibility for her family - which is what would happen if you married her, given that her ex isn't paying child suppport. If this is a dealbreaker for you, better to recognize it now.
