When you do get the chance see the specialist speak to him/her about Kuvan. As far as I know Kuvan needs to be ordered through a special pharmacy. You cannot just pick it up at your local Walgreens. For example, in my case my parents order my Kuvan through Medco and it is delivered to our door. Your husband will also need to see if he responds to Kuvan. Some people respond, and Kuvan helps them lower their phe levels. Other people do not.
If cost is an issue again talk to your husbands specialist. There are two organizations, BPPS (Biomarin Patient & Physician Support) and NORD (National Organization for Rare Disorders) that can help with the cost. My family has very good insurance, and our co-pay for three months of Kuvan is $50. BPPS actually contacted my family when I first began taking Kuvan, and they reassured my parents that if even this small co-pay was too much they would assist us. They are dedicated to making sure that those who can benefit from Kuvan have access to it no matter what your financial status is.