Sounds like you have a great setup for a beginner!
Keep up the water changes, if the tank has been up for 5 weeks you should be getting near the end of your cycle.
When they say your ammonia is high, do you know the ppm reading? EDIT: Just re-read the thread, do a bigger water change, say 50% and keep testing daily.
What capacity is your filter rated for? A 130L tank needs some reasonable filtration in my experience.