Best way to learn Irish?

I've always wanted to learn one of the old English or Celtic languages since i knew that they were gradually dieing out and as i have always visited relatives in Wales and heard them speak Welsh i was thinking of learning Welsh but i found out about 3 years ago that my surname is Irish and found out how it's spelled in Irish etc. and i found it very fascinating. Now that i know i have Irish heritage and that at some point my ancestors spoke the Irish language i would like to go back to my roots, so to speak, and learn Irish. I also would like to learn it cause there we'll be one more person in the world who knows one of the old Celtic languages that are at threat from not being spoken any more.

I know that surrounding yourself in the language is the best way BUT for one i'm 20 years old and don't have a secure job so i can't afford to go to Ireland for that length of time and second as not many people speak it i'll prob be speaking English more than Irish; oh and i live in the South-East of England, near London. I see Rosetta Stone advertised on TV and they do Irish but it costs like £100-300 which i guess would be worth it if i knew those things actually work, i can't really go by what they say, of course. I was wondering if anyone who has learnt Welsh, Irish, Cornish etc. etc. has found a method that works, i don't know what i'm expecting everyone else to come up with lol i'm just hoping someone might mention something that i have not thought of.
Thank Cody you were a lot fo help, and you got the same name as my dog hehe.

Hi Eire
I'm not sure what you mean by which dialect i'd prefer, i thought Irish was Irish, that there's only one Irish dialect lol shows how much i know.
er.. have not a clue, but if i have to choose one, maybe whatever dialect they speak in Northern Ireland. I found out my Surname is from these counties: Roscommon, Fermanagh and Offaly (i doubt the site i found that from is correct)
what dialect do they speak in the area those counties are in?
Hi cantilen
I sing along to Celtic Woman a lot but not many of their songs are in Irish. Can you suggest any tradtional Iirsh singers?

(just letting you know Eire i'm still waiting for your reply ^^)
Oh wow thanks so much Eire, you've have told me everything that i've been confused about for years. Nice to find someone who's so helpful. I'll look into those books more and see how much they will be in pounds (£) and where else i can buy them from, like a shop or something.

I still would like more replies to my question, incase someone else has more info they would like to share with me :)
Oh okay so i might find them in my town's library then, it's a bran new library too so it should be all up-to-date and have a varity of books, i hope i'll be able to find them. Thanks again!!

Is it Welch or Welsh? (the old language from Wales)?

My family originates from Wales and a couple of my relatives pronounce the language that my grandfather and grandmother used sometimes as being "Welch" while one says "Welsh". I just want to be absolutely sure because this is my heritage after all, and it means a lot to me. Someone that is well educated in this language please please help me clear this up. Thank You.