If you could take better pictures of the stones, when the sun's angle is optimal, it would be much easier to read everything.  That said, I will offer a free translation of the important parts of the inscription, filling in the blanks with educated guesses.  Here is what I managed to read from Abraham's stone:
"Here lies a dear man, Avraham, the son of Eliyahu Aryeh Bendel.  Avraham: An old man who all his life followed the good path.  Died aged 93 on Thursday, the 16th of Elul and was buried on the eve of the Sabbath, the 17th of the month in the year 5621" (Aug 22, 1861)
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Steve Goldberg
Jerusalem, Israel
Researching:
Sagan/Shagan family from Veliuona (Velon), Lithuania
Goldberg family from Vidukle, Lithuania
Susselovitch/Zuselovitch family from Raseiniai (Rassein), Lithuania

The second stone is much more difficult to read. I'll let someone else give it a try.  However, the Hebrew doesn't offer any additional important information over the English inscription, other than saying she was the wife of Avraham.
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Steve Goldberg
Jerusalem, Israel
Researching:
Sagan/Shagan family from Veliuona (Velon), Lithuania
Goldberg family from Vidukle, Lithuania
Susselovitch/Zuselovitch family from Raseiniai (Rassein), Lithuania

To the first I’ll just add that the first line of the first stone is a quote from genesis 24:1. 

the second stone:
H(ere)L(ies)
the woman Ms Pessele wife of Mr Abraham 
eighty seven years of age
she died Thursday (maybe Wednesday?) 6 Tishri
and buried Friday the 30th (?) of that month
year (5)622 by the short count (ie, not writing the thousands place)
May her soul be bound in the bonds of (everlasting) life 

the dates are hard to read and my numbers are likely off,  as it is unusual not to bury quickly. 

the last line is a boilerplate abbreviation used on both stones (and nearly all stones I’ve seen from the past few hundred years)

david dubin
teaneck nj