Where Can I get The R3/R4 Cards SDHC

The easiest way to get your hands on one of these cards is through ebay or second hand computer markets. Most retailers in most countries have been banned from selling these cards by Nintendo as it is causing them to lose royalties on selling games. There are many sellers on ebay who sell these for very reasonable prices. Also, you can try computer swap meets and second hand computer shops or small tech shops.