I organised a party for dh's 40th 15 months ago, but I did start planning it earlier than either of you, and budget wasn't really an issue (though didn't want to go completely mad).
We had it at home in a marquee in the garden - you can hire these, but we discovered that it's cheaper to buy than to hire twice, so as we'll want one for dd's christening I went ahead and bought it.
We hired flooring for it, chairs and tables and patio heaters, all from the same company.
For catering we had a hog roast - very nice. You pay for the hog and someone to cook and serve it - they tend to serve around 100 people, although we only had about 60 so had some leftover (they advised it can be frozen).
I considered hiring a bucking pig (like a bucking bronco but apparently smaller), but decided against it in the end.
We made the timing flexible, as there were people travelling different distances, so said to come any time from 3pm (or might have been 4), and catered for the hog to be ready to serve around 6 or 7 IIRC, so that most people would be there to have some at some point.
There were lots of kids coming too, so we got a new dvd for them, and put it on in the living room (had just had huge plasma installed) for them, as well as getting some of those giant garden games (jenga etc).
Don't know if this is any help to you or not, but there it is!