Do you think this coat will be a nice one and a warm one for a yorkie?

Yep.
References :

To be honest, I think its a little ugly. Your dog doesn't care about fashion, it cares about staying warm.

Try some more practical coats and don't worry about looks:

http://www.uniquedogclothing.com/dog-jackets.html
http://www.lovemypetsupply.com/dog-clothes-dog-jackets.html
http://www.terrificpets.com/pet_supplies/dog/apparel/jackets/index.asp?srt=LowPrice
http://www.petedge.com/catalog/thumbnail.jsp?Ne=1&parentCategoryId=197&Ns=PRODUCT_DAYS_AGO%7c0%7c%7cPRODUCT_SEQUENCE_NO%7c0&N=3034+1500014&subCategoryId=896&Nty=1&categoryId=895
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=18056&cmpid=01csesz&ref=3474&subref=AA&srccode=cii_10043468&cpncode=18-21097447-2
http://www.dog.com/
http://www.bizrate.com/dogsupplies/products__keyword–dog+jacket__sort–5__start–30.html
http://www.arcatapet.com/category.cfm?catnum=265
http://www.mydogol.com/wholesale-dog-clothes.html
References :

looks cute.. why did you have to show me that? Now my Crested needs one!
References :

lt looks a little bulky and uncomfortable to me, imagine when if it gets wet, she'll look like a drowned rat.
Although if you like it that's all that matters, l'm sure she'll wear whatever you get her.
References :

It is sooo CUTE! I love it so much. It looks so warm. I've been looking for a coat warm enough for my Dachshund, but he's a boy dog. I want it so BAD! IT looks so CUTEEEEE!! I WISH I had a girl dog to put that coat on.

It is not UGLY, like some people said.

YOUR dog would like a little princess..

References :

yes it looks warm(:

-kaitlyn.
References :
dog owner.