If you need a boar to hire check the GOS website, theres a list of boars whose owners are prepared to hire or take in your sow but at 11mths you boar should be well capable of doing the deed.
www.oldspots.org.ukIf your girl isn't interested it may the fact that he's already got her in pig, is she still coming into season? Girl pigs come into season roughly every 20 days so if he went in when she was in season he may have caught her first time which why 3 weeks (20 days) later she's not interested. You'll know if she's coming into season as he will chase her madly, her tush will be very pink and if you scratch her back she'll squeal in delight!
If you don't know this i suggest you get a good pig book to explain things and help you understand what will be involved at farrowing. Try Carol Harris A Guide to traditional pig keeping or Richard Lutwyche's little pink national trust book, both very good.
HTH Mandy