Vintage Dual 1228 Turntable : worth to upgrade cartridge ?


I have from my college days (1977) Dual 1228 with original fitted Shure M95ED cartridge .  It is maintained well , not used for about 20 years in between , but just cleaned , lubricated , resoldered some loose connections , etc and just runs great for me. 
I am not too much into analogue , so not planning to do big time investment into new TT , Phono preamp , but if  can get larger benefit by replacing the Shure M 95 ED with some new cart upto $ 200-300 , I would like to do it . 
My Phono preamp is very low end Cambridge Audio MM 551P . To go with new upgraded cartridge , I may even consider to buy used Phono with budget of $1000 . 
I would appreciate advice form FMs here , where I should spend my money to get most benifit on sound improvement . New cart , new phono ? 

radni
I just ordered a JICO Stylus SHURE N95HE ( Hyper Elliptical ) which will fit onto my current cartridge M95ED , I hope it should give sound improvement. It should arrive within a week.  I will order a new Cart Shure  M97 or AT soon. 
Thanks to you all FMs , for your valuable help to understand this issue and make a decision. I was kind a shaky to start this topic or ask here , but I am happy to note that FMs have been very forthcoming in sharing their experience, knowledge and helping . That's what I like about this community. 

Radni,

JICO is an excellent stylus. The Audio Technica will have a little more sparkle than the Shure cartridge. If your preamp has tone controls don't be afraid to use them. Adjust to taste and enjoy the music. 

You can always find additional drop out headshells for the Dual so swapping cartridges will be easy. 
Make sure to use the Dual alignment guage when installing your cartridge. It will ensure proper over hang. 

Also a good idea to remove the platter and let some machine oil drip down the platter race and onto the platter bearing set. 

Norman
Thanks Norman,
JICO SAS stylus was very expensive for me, so I settled for JICO N95HE.
Thanks for suggesting about spare "headshells" for Dual , I will search for them  on eBay . Sounds worth having them.
Where to get Dual Alignment Gauge , what price ?
I did oil the TT  at places  as per chart in the service manual  . I used 3 in 1  machine . But I will see about putting some oil on bearing if not already done by me. 
 I must have 6 Duals,I ran a 1229 and a 1219 for years,my last cartridge upgrade years ago was a Goldring 1042 or 1022.A couple years ago I installed my Signet AM50 on my Dual and it sounded very poor compared to on my secondary P+E table let alone my Rega.I would plan on replacing the Dual or staying in low price cartridge range.Spare headshells are the way to go,I have about 5 for the P+E and the old Shure V15 sounds good.Duals were good in their day but just can't produce soundfield.
Playpen,

Thats total Hogwash. A properly set up 1229 will blow the skirt of most entry level tables. Mine certainly does and it isn't just my opinion either.  Come listen anytime.  If your P&E table is vintage, it was built by Dual. Dual bought P&E back in 1972, and built their tables until about 1978 when P&E was phased out. 

My Dual 1229 using a Grace 747 sounds better than my grease bearing Garrard 301 using a SME 3009.  Both were infinitely better than my Linn LP12.  

Norman