Hiya

I'm away up in Scotland so too far to be any practical help, but yes, the usual is to take your gilt/sow to the boar. 18 months is getting on slightly in pig terms, so don't leave it much longer before you mate her or you might find she struggles to conceive

In terms of what to mate with - Kunekune would be the obvious choice, but Berkshire is also a good meat cross I'm told. We've used our Kune boar on our OSB sow, and the resulting piglets were super, but I wouldn't do it with a Kune sow because of the size difference and potential problems at delivery. Both breeds have a website, with a list of breeders - best thing is to check them and see who is closest. Make contact with a few people and see what they say.
Avoid putting her to a boar who is significantly bigger than her too, incase she gets hurt during service. She'll have to support him for as much as 30 minutes, so you don't want her back legs giving out under the weight. When we have pigs here for service I like to keep them til at least 4 weeks after service, this gives you time to check they're definately in pig and allows longer to make sure the embryo's are well implanted and reduces the risk of abortion when travelling home.
You want to make sure she's up to date with worming and if you're vaccinating for anything (erysipelas and parvo being the most obvious ones) make sure it's all done before she goes too

The other thing to consider is
why you are breeding ? If it's to give a supply of pork for your own freezer then fine, or if you have buyers lined up and prepared to wait 6 months for weaners, all good - but be aware of how many people there are selling pigs around you and what the demand is like in your area. You're lining up for a summer farrowing and having pigs ready for sale around September time - the demand for weaners does tend to slow in the last half of the year. Ask yourself, "if none of these piglets sold and I had to keep them all, could I manage and do I have the facilities to be able to house them ?" If the answer is no, don't put her to the boar.
Sorry, don't mean to preach

- but it's essential you really think ahead before breeding, for your sake as much as the pigs

HTH
Karen