Don't kill the messenger... but here is the bad news. You are already off track. There are scam sites on the internet that will tell you there are surname family crests. The first tipoff that they are scams is that they use the word "crest," which is really just the design on top of the helmet (think of a bird's crest, like on a cardinal). What you are looking for is a coat of arms, not a crest. The second tipoff that they are scam sites is that they associate surnames with arms. Duh! There are hundreds of coats of arms owned by people named Smith, for example, but they sell only one. So they are selling you another person's coat of arms!!!!
I highly recommend you read this for more information:
http://www.heraldica.org/faqs/mfaq
So here is the deal. Find out where YOUR immigrant ancestor came from in the old country, when he was born, and in what city or village. Then contact a heraldry society and ask them to do a lookup. Or once you know where YOUR family came from, write someone there who has the last name. Most likely they are your distant cousin and can supply you the information you are looking for.
If you cannot find an ancestor who used a coat of arms, you can create a new design. The best thing to do is to sign up for free heraldic design assistance at the IAAH. They can design traditional arms for you based on your ideas, instead of quasi-heraldry by a tattoo artist or fake heraldry from a surname coat of arms peddler on the web or at the mall.
http://www.amateurheralds.org/