Hi,
Worm her now (if you've not done so already)
Up her feed rations a bit (be carefull not to go over the top though)
Are you bringing her in to farrow ? If so, move her there 3 -4 days before she's due. I find it easier - that way you can rig up lights to see what's going on and the heat lamp and creep area for the piglets (and it makes the through the night checks easier) If you're planning to be there for the birth (which I'd definately advise, especially as it's her first) get some old towels to rub the piglets to dry them off, a big sturdy cardboard box to keep them contained til she's finished - saves anyone getting squashed !
Once you are able to express milk from her teats labour should start within 24 hours. If, once she's farrowed, there's no sign of milk give her a shot of oxytocin to help bring it in (it helps expell the afterbirth too if it doesn't come with the last piglet). You'll need iron injections for the piglets if indoors, or put a lump of soil in for them to nibble on. Another thing which is handy to have on hand incase she gets snappy is stresnil (not sure if i've spelt it right) this will help calm her. Some pigs can get quite snappy and stressed with the piglets, first timers are a wee bit more prone to it I think.
Once she's farrowed cut back a bit on her food for a couple of days, but by the time the piglets are a fortnight old you'll need to allow an extra half pound of food per piglet to her ration, upping to a pound by the time they are 4 weeks old.
A broad range antibiotic never goes amiss - just incase you have to do an internal or retrieve a stuck piglet.
Argh, I've probably put the fear of god into you now - sorry

It's not too bad. Just be prepared, check her hourly once her milk's in (that way if she appears to be distressed you can act quickly) and enjoy it - the piglets are so worth it !
HTH
Karen x