Hate to say it but it was a bad idea for you to get 25 defence. Max your defence out at 10. Either that or get 10 prayer. One or the other. This way your combat level stays low and your range level can get higher.
Its not
totally ruined. You can still get some good pk's with it but if you wanna make a really good one start over and get 10 defence max.
Good idea is to keep level 1 defence and prayer though

As long as you have good food (lobbies and swords) you don't need defence at all.
Just a few idea if you want to try them out.