Yes. You can pre-paid your credit card and then your credit limit will automatically increase with your base limit + your prepaid. Then your funds available is equal to base limit + your prepaid. Then your buying power is based on your funds available. Not based on your limit.
eg. Limit 1000, funds available 500 (means you already spent 500 on the card), then buying power is 500.
Limit 1000, prepaid 2000, funds available 3000, buying power 3000.
Limit 1000, prepaid 2000, funds available 2000 (means you spent 1000 already), buying power 2000.