Since you have provided rather incomplete information regarding your mother, I shall be making some assumptions while giving you suggestions.
I am not sure for how long is your mother on dialysis and how much urine she makes in a day but ordinarily patients who make minimal urine(<300-400 cc) are expected to gain few kilos between dialysis sessions if their intake is proper. If your mothers weight remains unchanged after dialysis, there are two possibilities. Either she is making good amount of urine or she is eating very poorly. If latter is the case, then it is a bad sign since she may need more dialysis. Scientific studies have indicated that patients who have no kidney function at all and who are not dialyzed adequately have higher mortality. On the other hand, if she is eating properly and makes good amount of urine, her kidney function needs to be reassessed(remeasured) to determine that if she in fact needs dialysis or not.
As far as recommending a transplant center is concerned, I shall refrain from advising you for or against any particular center on a scientific basis as I am not aware of any studies showing superior outcome from certain center over the other. However, you may consult with your local nephrologist who may advise you on this subject.