does anyone have database, programming language/framework suggestions gui indicate sale system?

our association indicate sale component extras, such organization receiving functionality, sales method story etc. the sure emanate component designed morally martial up, takes too enlarged fixes hoop requests the customers. also, tide record controlling (progress database, swell 4gl language) incurs definitely bit chartering rubbish the business due mutli-user assent fees database connectors etc.

after lot contention looking substantially start over cut (while surpassing tide product during slightest being). looking integrate things:

1. create component good gui front finish (it now chui concentration built proceed allows us redesign front end... layering fortitude business explanation gui...shudder).




2. create component ability modularize opposite functionality product doesn't have consolidate features. keep cost down the tide business wish simple functionality devaluate cost tag. bells whistles accessible those wish them.




3. use repremand settlement patterns product easy supplement change any biased during any (i.e. change database change front finish but wanting rewrite concentration many it). problem now since swell 4gl formula directly collected opposing database. little changes database requires lots formula recompiling.

our new component linux based, luck fan concentration providing functionality some-more windows boxes.

so i'm looking any suggestions database and/or horizon programming language(s) someone competence advise arrange product. anyone trust domain competence means indicate us right instruction even have ideas avoid. have deliberate .net sql demonstrate (we don't need an craving turn db), nonetheless border us windows (as distant i know anyway). i have listened mono minute .net formula linux environment, nonetheless i don't know many yet. we've also deliberate java mysql formed implementation.

to promulgate looking following:

1. keep chartering costs down record arise product (oracle, yikes! mysql, nice.)




2. deliver fortitude simply maintainable supportable.




3. a fortitude member able controlling "old" hardware by chui front end. (some the business have 40+ terminals ton money method modify over pc).

suggestions appreciated.

thanks

[update]
i should note now behaving sum cost analysis. doubt commanded give us integrate "educated" options feeling consolidate analysis. anyone share experiences/suggestions client/server setups appreciated (not only those have trust indicate sale systems... only bonus).

[update]

for anyone interested, finished adult going microsoft dynamics nav, ls sell (a plugin indicate sale several things) following (and now operative on) customization work tip that. setup gave us total advantage carrying entirely integrated g/l system, the tide component lacked.