If you do have a lot of fleas, you still don't have to use
chemicals in you house. Use the Frontline/Advantage as
suggested, for at least two months.

Vacuum and shampoo all carpets. Cut up a flea collar and
put it in your vacuum bag to kill fleas that you vacuum up.
At the same time, wash everything you can wash - bedding,
pet beds, small rugs, etc.

Doing these things all at once will significantly reduce
a flea infestation.

depends on your area  I have company which charges up front 300 at the
beginning of the contract than 79 a year which it does 3 times  extra times
are 49.99 each

BOnce upon a time you could get the council exterminators out, free of
charge to anyone who called if they had a cat flea problem. As with
all things, people abuse the service, & in the end, everyone end up
paying to make up for the freeloaders.
I don't know where you live Clare, but it might be worth asking them
to come out.
In my opinion, they are the best one people to get rid of a flea
problem because they guarantee the work.

These days, if you want the to come out to you, as long as you are
ready to receive them ( ie: you are all tidied up, & it is easy to get
under the beds, and move the 3 piece ect), then you will be fine,
because they charge by the hour. It's around ?36 per hour, which
starts when they leave the depot to come to your place, so if you say
2-3 hours max, you can estimate the price. Mind you, as I said, if you
have a problem after that,. they will do a respray for free...
They do a brilliant job & it's worth every penny when you consider the
exchange.

That is how much my council charges, of course yours might be
different, but I would say that it is well worth checking them out.
The spray that  Paul mentions, is good, but a bit pricey if you intend
to get the whole house done. You need to do every singe pace where the
cats go ( & don't go too, becasuse fleas jump amazing paces away!!),
right down to under the sofa!!

Good Luck Clare,
Sheelagh >"o"<