grammar - When I am quoting something does it need to be incorporated into my own sentence? (Also, should I use an ellipsis?)

I am writing an essay for my English class. At one point I make a statement about the book and end the sentence. Afterwards I've inserted a direct quote from the book on its own. Here's an example:

Jake is in love with Kate. "Jake looked at Kate and his heart began to
race..." (Johnson 102)

That is exactly how I have it written. Is this correct, or should the quote be within a sentence? Also, is it all right to use the ellipsis there because I left out the end of the quote? Should there be a period after the citation? Ugh!!