[The Corsair]

Basically the bassist and guitarist of Unwritten decided to leave and start their own project which caused the drummer to leave as well.
This basically leaves me wondering what the hell to do next. I am in another band in which I play drums but we've yet to find a singer and guitarist and even then I'm not very experienced with drums.

Most people here have been in and out of bands so I want to see if I can get some advice from you guys.

[Ramshackles]

Keep writing, recording and improving. Use the recordings to entice new members.
Play acoustic gigs. My band actually doesnt have proper drummer or bassist. We've played a total of 2 acoustic shows and then holed up to record. But based on those shows and a couple of recordings we passed around, some people we know and like in the local 'scene' have come to us saying if we need help with the next show, they are in.

So - keep writing, play with whatever you've got and get to know other musicians in the area.
I wouldnt go round asking anyone you know who plays drums/bass to fill in - they are more likely to say no, and if you don't have a personal attachment to them you could be more likely to end up in the same situation.

[The Corsair]

Well I don't have a great voice for acoustic gigs nor can I play guitar. We also haven't been in studio nor do I own any recording gear.

[Ramshackles]

Well, then you have lots of fun things ahead!
So you only play drums, but you say you aren't very experienced on them? Get experience! Play religiously. Go out to local gigs and meet bands, musicians that you like, let them know you are a drummer.
As for recording, all you need to get going is a mic and an interface, which can cost peanuts. See cheap recording tips for advice.
Main point though is, what do you want to do? Once you know, go and do it

[The Corsair]

There isn't much of a scene in New Zealand for my own tastes (part of why I'm moving when I can).
I'll need to save for a drumkit (and probably lessons)
Thanks for the advice Ramshackles!

[Dutchbeat]

go for the songwriter position....

well, seriously
grab it while you can!