Yes, of course you can give your SCBCD after your SCJP.
The current version of the exam is SCBCD 5. If you are all together new to EJB's, then go for EJB 3 in Action. It will help you lay a strong foundation. Then pick up PRO EJB 3 for a wondeful and detailed explanation on JPA.
If you are sincerely willing to write the exam, then you also have to go through the EJB 3 Specs apart from the above mentioned books.
SCJP 1.4, SCWCD 1.4 - Hints for you, Certified Scrum Master
Did a rm -R / to find out that I lost my entire Linux installation!