Basically the entrance fee of £3 sounds far too low for guest nights. The normal price seems to be £8 - £10, or even more occasionally for top acts. But of course it depends on the size of the premises and of your audience - the more people you can pack in (assuming you can attract them in the first place), the lower the entrance fee can be. With regard to the question "how do I find 4 more Mondays?" If you're trying to fit in more guests, why not just have a monthly session instead of a fortnightly one? Also, if you don't charge for sessions, why not consider charging a nominal amount, say £1 or £2 - you can explain that it all helps the club keep going and to allow you to book more acts, etc. Try to involve you members more, and make them feel part of it and not just punters.

Apologies for rambling on again - maybe I should call myself Rambling Syd Scrumpo ;-)