Is Dracula a real person or was he invented by Bram Stoker?
probally invented
There were two demi-kingsr in the Balkans: Vlad Dracul (the dragon) and Vlad Dracula (Son of the Dragon). The character created by Bram Stoker had many similarities with Vlad Dracula but then a few references that would be 'deal-breakers' as far as confirming the identity of either as the other. I think Stoker created the character with the intention of confusing him with the historic ruler.
If you understand English well enough to even consider reading Dracula, you will be fine. If you can't understand the language used, you are quite possibly illiterate (or simply young and not yet educated to that level).
Were there any other books written by Bram Stoker besides Dracula?
Yes:
What pact does Mina hold with Dracula in Dracula by Bram Stoker?
Well, originally, the book was suppose to have a romantic element, with Dracula himself, posing as a handsome young man, for Mina to fall in love with. I'm not sure why it was changed, but maybe you or someone else can find out, but then, I guess there is some romance within the story itself.
Francis Ford Coppola created the movie "Bram Stoker's Dracula" (1992). There the (very) romantic aspects of the story are added or re-added very clearly leading to the conclusion that Mina saves Dracula from hell by cutting of his head in the very presence of God. She sais to him "Our love is stronger than death" just before she swoopes Dracula's own sword against her grand lovers neck.
On this site, they claim that it was Old English slang for "beautiful" lady... http://www.calandrastudio.com/websitepages/blooferlady.html
Wikipedia concurs: http://en.wikipedia.org/wiki/Dracula
Not sure, because I can't find any official source, but that might be the meaning.
The Norton Critical Edition of Dracula states that the term "bloofer lady" is "Child talk for 'beautiful.'" If you think about it, in English dialect, no less spoken by a small child, "beautiful" could be corrupted to "bloofer."
What was Jonathan Hawker's job in Dracula by Bram Stoker?
Jonathan Hawker was a solicitor (lawyer in US) and was required in Transylvania to assist in a legal matter involving a property transaction.
What links did Bram Stoker have with Whitby?
Bram Stoker holidayed in Whitby, and it is thought that he drew his inspiration for Dracula from Whitby Abbey and the town. In the book, Dracula is shipwrecked in Whitby and comes ashore in the form of a dog.