First, when reconnecting with a past SB I will generally give her the same allowance as in the past. I see it as a continuation of the original agreement and there is no need to renegotiate or even discuss - especially as you may inadvertently be negotiating against yourself. I.e.: "Since you ask, I need (old amt) plus $300)."

 
But as she already said something like "anything will help..." she's opened the door to accepting less than the old amount. This suggests she is desperate due to some unplanned needs (car repair, rent, legal fees/fines, etc.). However, if you are comfortable with the original amount, it would be kind of a dick move to short her just because you can.  

 
Next, is the bipolar crap.  I've been there and have vowed to never return. Ultimately it cost me orders of magnitude more cash, grief, and time than it was worth.  Maybe if you are sure this will be a one-time BCD, and you don't have better, more stable/less destructive options at hand... but adding more risk with no additional reward when it's not necessary seems ill advised.  Sometimes, an overabundance of pussy is not a good thing. But only sometimes. LOL  

 
Life is good

 
The Cat