Corel X3 to PDF, poor resolution

Hi everyone,

I´m using Corel Draw X3 and trying to save my work using the "publish as PDF" option. However I get a very poor resolution in my graphs and also with the text (particularly in the "i" and "l" characters). I'm using a very small font (2,5 and 2 pt) and my draws are JPG files.

I really need to know if there is any solution to this problem and which are the options I have to choose when I publish as PDF to get the best result. i´m not going to print my work I only need it looks clear in the computer.

Thank you!!!