Simple members website - rough quotes needed tonight/tomorrow morning

Firstly, let me apologise for not being able to give very much detail, and for not having a definite job offer.

We are a charity that assists our members to find employment, and as part of that we have a simple jobs board accessed by secure login (username, password, first name, surname, are stored within the site). There are between 40 - 80 jobs on at any time, with around 2,500 people using it over the course of a week. We are having problems with our current provider, and frankly the website has gone to pot. We are planning a bigger, better members' website in Q2 2012, but in the interim we need something to take on the job, as we are letting people down. We are currently debating over whether to bring this in-house and try to create it using the CMS of our main website, or whether to have a new one built. If we do build a new one it will only be live for a few months, before our main site is released.

Designs can be provided, but the development is needed.

Any vague ideas of cost (including monthly maintenance fees) would be welcome - we are going into a meeting to make a decision of direction midday tomorrow, so need responses by then (sorry about the quick turnaround). I will be checking through the evening, so please feel free to ask questions.

Thanks all!
I have just read the T&Cs (the section about listing yourself as a not for profit) and would like to point out that whilst we are a charity, we do not expect any kind of special rates - you get what you pay for!
I know that it is very difficult to ask for guidance on this with the limited info I have been able to give on this at the moment, but I am having to talk to a provider known to us (not that I want to) at the boss's (my boss, not Hogg) direction. They have quoted £5K. That seems like a lot - any comments?

Well, if you've given them the info provided here then they are probably hedging their bets with the quote. That's kinda the problem, if you can't verbalise what you need in a concise project plan then any developer worth their salt will build a LOT of contingency into the quote to accommodate 'scope creep'. I'd suggest you put together a proper brief with visitor flows and exact requirements and then re-approach the developer for a firmer price. Hope that helps.