All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Undoubtedly, performing ‘Umrah during Ramadan has a great virtue and abundant reward. To indicates its virtue, it is enough to mention the Hadeeth in which the Prophet, sallallaahu ‘alayhi wa sallam, said: "‘Umrah in Ramadan equals (in reward and virtue) Hajj." In another narration, he added: "…Hajj with me." [Al-Bukhari]
Nevertheless, this great virtue does not reach the virtue of the obligatory Hajj. The accepted Hajj has no less a reward than Paradise. Even if we adopted the view that ‘Umrah is obligatory, it is not sound to think that performing ‘Umrah absolves one of liability to perform the obligatory Hajj. But it is permissible to perform ‘Umrah before Hajj.
Consequently, you can seize the opportunity and go to ‘Umrah during Ramadan, or any other time, because of its great virtue and in compliance with the view that it is obligatory. Then, you perform Hajj when you are able to. As such, you will not miss the two altogether.
However, this should be done if you most likely believe that you are financially able to perform both Hajj and ‘Umrah. If you most likely believe that you are unable to perform both Hajj and ‘Umrah, the preponderant view is that you should wait and try again and again perchance Allaah Facilitates Hajj for you.