Jen,
I know the money is tight but scrape some together and consult someone else. From the answers your solicitor is giving you, it sounds like he's "there there"ing you. The HO has and will continue to split up families. If he's counting on sympathy in that regard, he is counting in vain.
Find someone who knows immigration law. There are websites listed on this page where you can get a ref. From what your solicitor is telling you, I have a strong feeling this is not his area of speciality and with the constant changes taking place, you can't be sure someone who's not knee-deep in it is up to date enough to give you good advice. As a matter of fact, considering their treatment of your case until now, it is almost certain they've never got themselves up to date on the law at all.
Get a second opinion. Please. This can end up working out worse than you can imagine. You can end up barred for years. If the person you consult tells you the same thing your solicitor is, at least you'll have a peace of mind. It's worth the money, it really really is.
It's nice that he's saying he'll lodge an appeal right away but because you applied out of status, you might not even have a right to an appeal and he should have told you that. There's just so much..I dunno if I'd say wrong but certainly off in this situation that outside help is needed. And absolutely, positively find someone who specializes in immigration law. It is absolutely essential.